Tropical Aquarium Fish

Introduction

Since even a small amount of material can be difficult for a newcomer in any field to digest and retain, the novice aquarist may wish to read only the “Good First Fish” section to begin with. Then, while consulting a good beginner’s book (the most essential item for any novice aquarist to own), she or he should choose a small number of possibilities for the fish with which to start her or his new tank.If someone familiar with the local fish stores is available, it is wise to get a recommendation for where to shop for fish. Otherwise the beginner should try looking for shops that specialize in fish, either exclusively or as a major part of their business. This is no guarantee, of course, but it does improve the odds of finding a good store.

If, upon reaching the store, none of the selected fish can be found, the novice should refrain from purchasing any fish that he or she is unfamiliar with, even if recommended by the store’s employees. (Some stores have very knowledgeable staffs but many, alas, do not. It will take some time before the new fishkeeper can discern a good store from a bad one, or good advice from poor.) At this point, another store could be sought out or further reading done to determine alternate choices for first fish.

Assuming that desirable choices for first fish can be found, the beginner should carefully inspect the specimens for sunken bellies, sunken eyes, clamped fins, labored breathing (often with gill covers quite extended), and any sort of external blemishes that might indicate parasites or disease. If the fish appear healthy, the novice should ask to purchase a very small number of fish, depending on the size of the tank and the fish. A twenty gallon tank is a good size for a beginner; it is large enough that the water conditions will be fairly stable, yet small enough that the beginner is not intimidated. For this size tank a single fish of one to two inches in length, or three or four smaller fish, is the most the novice should start with. (If more fish are put into the tank initially, poisonous ammonia will build up and kill the fish. If the tank population is built up gradually, however, this will not be a problem. To understand this gradual introduction of fish, known as `cycling the tank’, the novice should read about the nitrogen cycle in his or her aquarium book, or the NITROGEN CYCLE section of the BEGINNER FAQ.)

Good First Fish

If we define a good beginner’s fish as one that is easy to feed and care for, hardy, able to live in a variety of water conditions, and attractive, then there are a number of widely available fish which fit the bill nicely. Many of these are regularly sold as beginner’s fish. But watch out! Many of the fish sold as beginner’s fish really are not well suited to that role.Many of the smaller schooling fish make ideal first fish. These include White Cloud Mountain Minnows, the several commonly available species of Danios and Rasboras, and most available species of Barbs. For those with a slightly larger tank, Rainbowfish make a great schooling fish. Corydoras Catfish are ever popular schooling catfish.

While many beginners are tempted to get just one or two of each of several different schooling fish, this should be resisted. Schooling fish do better if there are several of their own species present for them to interact with. A minimum of six of each of the midwater schooling fish is recommended, while four is the bare minimum for Corys. In the long run, a school of a dozen fish showing their natural behavior will be more pleasing than a mixed group of fishes unhappily forced to share the same tank. (“Mom, why is that one fish hiding behind the heater and that other one just hanging in the corner?”)

Of course, as mentioned in the introduction, the population needs to be built up slowly, two or three fish at a time. The aquarist might, for instance, build up a school of eight Rasboras of a certain species, then turn to building up a school of six of a species of Cory Cats.

Some Cyprinids

White Clouds, Danios, Rasboras, and Barbs are all Asian fish related to the Carp and the Minnow. All of these fish belong to the family Cyprinidae. White Clouds, Danios, Rasboras, and Barbs are small, active, hardy, and colorful.

“White Cloud Mountain Minnows” - Tanichthys albonubes

Found in mountain streams in China, White Clouds can be kept in unheated tanks (down to 55F). Some people advise against putting these fish in tropical tanks but I have found that they do fine in heated aquaria as well, as long as the temperature is not kept above the mid 70s. They can be fed any small food and they spawn often but fry will not be seen unless the parents are removed to another tank. White Clouds are brown with a red tail and a silvery white line down the side that shines in the light. They get to be 1 1/2″ long.

Danios

Several species of Danios are often found in pet stores, including the Giant Danio - Danio aequipinnatus, the Zebra Danio - Brachydanio rerio, the Leopard Danio - Brachydanio frankei, and the Pearl Danio - Brachydanio albolineatus. These fish are fast swimmers and are always in motion. Different patterns of blue markings allows one to tell these fish apart. Most Danios stay under 2 1/2″ long, although Giant Danios can get up to 4″.

Rasboras

The most popular Rasbora is the Harlequin Rasbora - Rasbora heteromorpha. A very similar looking species, Rasbora espei, is also available, as is the Clown Rasbora - Rasbora kalochroma and the Scissor-Tail Rasbora - Rasbora trilineata. Orange, brown, and red are usual colors for Rasboras, and their stop-and-start swimming makes them interesting to watch as a school. Scissor-Tails can get up to 6″ long and Clown Rasboras up to 4″ while Harlequins stay under 2″ long.

Barbs

By far the most commonly seen and commonly cursed Barb is the Tiger Barb - Capoeta tetrazona. It nips the fins of other fish if not kept in a large school of its own species and because it is over-bred it is susceptible to diseases. Several aquarium morphs are also available (such as the greenish “Mossy Barb” and an albino variety) but these are even more sickly and often deformed.Don’t give up on the Barbs too fast though, as many are well suited as first fish, especially for those with moderate sized tanks. Capoeta titteya, the Cherry Barb, is a terrific little barb - up to 2″ long and with a wonderful orange-red color. Mid-sized barbs (up to about 4 1/2″ long) include Clown Barbs - Barbodes everetti, Rosy Barbs - Puntius conchonius, and Black Ruby Barbs - Puntius nigrofasciatus. The artificial morphs (long-finned, albino, etc.) of the Rosy Barb should be avoided though, as these tend to be sickly. Checker Barbs - Capoeta oligolepis and Spanner or T-Barbs - Barbodes lateristriga are large, peaceful barbs (Spanner Barbs up to 7″ long). Unless you have a very large aquarium avoid Tinfoil Barbs - Barbodes schwanefeldi. They grow to be over a foot long!

Note that many barbs don’t school as “nicely” as do Danios or Rasboras, but most should be kept in schools nonetheless. Also note that many authors may put all of the above mentioned species in the genus Barbus.

Corydoras Catfish

Cory Cats are members of the family Callichthyidae, a family of armored catfish from South America. Corys are small (generally 2 1/2″ long or less), schooling fish that are always searching the bottom of the tank for food. There are at least 140 species of catfish in the genus Corydoras. Some of these are quite delicate and die quickly even in the hands of experts. The fragile ones, however, are rarely seen in pet stores and are high priced when they can be found. The Corys you will see for reasonable prices are hardy and can even survive in a tank with low oxygen as they can swallow air from the surface and absorb it through their intestines. Some Corys you may encounter are the Bronze Cory - C. aeneus, the Spotted Cory - C. ambiacus, the Leopard Cory - C. julii, the Skunk Cory - C. arcuatus, the Bandit Cory - C. metae, and the Panda Cory - C. panda.Corys generally feed at the bottom of the tank and special sinking foods should be fed. These include sinking pellets like Tabi-Min and frozen blood- worms. Care should be taken to insure that all frozen foods are eaten quickly as they decay rapidly and can foul the tank. Don’t overfeed!

Rainbowfish

Rainbows are extremely colorful fishes native to Australia, New Guinea, and Madagascar. Like the Cyprinids described above, Rainbows are schooling fish and should be kept in groups of six or more. Larger, somewhat more expensive, and harder to find than many of the schooling fishes already discussed, Rainbows are easily cared for, active, and make good first fish for those who want to try something a little less common. Look in your dealer’s tanks for the Australian Rainbow - Melanotaenia splendida, Boeseman’s Rainbowfish - M. boesemani, Turquoise Rainbows - M. lacustris, and the Celebes Rainbow - Telmatherina ladigesi.

Good Second Fish

The previous section talked about good fish for the complete novice aquarist. This section will discuss good fish for beginning aquarists who have had some experience or who are willing to do more careful research and shopping before buying their fish.Many of the fish recommended here are every bit as hardy, adaptable, and easy to care for as those in the first section. However, in the first section I was able to recommend whole groups of fish or at least say to watch out for only a species or two in each group as bad choices. Here, however, the groups will be quite mixed with many good choices and many poor ones. Also, some of the fish in this section are hardy only if some special needs are cared for. If you wish to successfully keep fish from these groups you need to be sure you know which species you are getting and what their needs are.

Why bother? If you are a complete novice, perhaps you shouldn’t. The great choices from the “First Fish” list should allow you to get your feet wet (as it were) with minimum risk. However, as you gain experience you may decide to give some of these fish a try. Many are quite beautiful and/or have interesting behaviors and some aquarists become so taken with them that they join specialist clubs just to learn about and trade one group or another of these fish.

Loaches

Loaches are long-bodied Asian fishes distantly related to the Cyprinids (Barbs, Danios, etc.) described above. Like Cory Cats, loaches have a down-turned mouth equipped with barbels - an adaptation for living and feeding at the bottom of ponds and streams. They will scavenge the tank bottom eating the food missed by other fishes, but you should take care to see that they get enough to eat. Special sinking foods are a must.Some loaches are sensitive to poor nitrogen cycle management, which is why they are included here, rather than in the Good First Fish section. Once the tank is established and the beginner seems to have gotten the hang of maintaining a tank, however, loaches make great additions to most community fish populations.

The most commonly seen loaches are the Kuhli Loaches - Acanthophthalmus species. These are long, ribbon-like fishes which grow to be 4″ long. Brown with yellow stripes and bands, Kuhli Loaches are shy and spend a lot of time buried in the gravel.

Another popular group of loaches are the members of the genus Botia. Clown Loaches - B. macracantha, Yo-Yo Loaches - B. lohachata, Skunk Loaches - B. horae, Blue Loaches - B. modesta, and Striated Loaches - B. striata are all seen in the hobby. Some of these (notably Clown and Blue Loaches) can get big, but they grow extremely slowly and can live in a small aquarium for several years. Loaches will often be happier if kept with a few of their own species.

Weather Loaches - Misgurnus fossilis and Spotted Weather Loaches - Cobitis taenia should be avoided. They are cold water species and have the unfortunate habit of jumping out of aquaria, especially at the approach of a storm.

Dwarf Plecos

“Pleco” (a shortening of the now-unused genus name Plecostomus) is the common term used for suckermouth catfish of the family Loricariidae. As mentioned below in the Bad First Fish section, common Plecos (Hypostomus species) are often sold to beginners as algae cleaners. Unfortunately, these fish get too large for the relatively small tanks of most beginners.Some species of suckermouth catfish, however, do stay small enough for most beginners to keep. The Clown Plecos of the genus Peckoltia have alternating transverse bands of darker and lighter brown, tan, or yellow and generally stay under 4″ long. The Bristlenose or Bushynose Plecos of the genus Ancistrus possess, as their common names imply, numerous projections from the area between their eyes and mouth. Within each species the bristles are larger on the male, especially near breeding. In fact, Bristlenose Plecos are among the few Loricariids to be successfully spawned in the home aquarium.

Otocinclus Cats, often just called Otos, are the smallest Loricariids and will clean algae from live plants without hurting any but the most delicate of them. Otos sometimes die shortly after purchase for no apparent reason, but if they make it past this critical time they make very good community tank residents.

While the various suckermouth catfish will indeed help to keep the aquarium free from many common algae types, the beginner should not make the mistake of thinking of these fish as simply algae eaters or scavengers. They should be given foods intended just for them, such as zucchini which can be blanched or weighted down to sink it to the Pleco’s level. Some fish food manufacturers have recently realized that there is a market for specialized Pleco foods and now sell products such as sinking algae wafers which fit this bill nicely. These foods should be fed in the evening when the light reaching the tank is low, as most Plecos are more active at this time and most other fish which might compete for the food are less active. Pieces of (uncoated) driftwood in the tank are also important for many Pleco species, which rasp at the wood and ingest the scrapings. By the same token, Plecos should *not* be kept in wooden tanks, or even acrylic ones for that matter, as they may chew into the tank material damaging it and/or themselves (by ingesting toxins or undigestible matter).

Pleco species can be quarrelsome amongst themselves and may be picked on by other fish due to their generally slow-moving nature. Provide a hiding cave for each Pleco and give them territories proportional to their size (e.g. 10 gallons for a 3″ fish.)

Tetras

Like many of the fish in the first section, Tetras are schooling fish and should be kept in groups of six or more of the same species. Tetras are native to Central and South America and Africa. In some regions of South America the water is quite soft (very little rock is dissolved in it) and acidic. (Another way of saying “acidic” is to say that it has a low pH - one below 7, which is considered “neutral”. A strong acid has a very low pH. Liquids above pH 7 are said to be “basic”.)Unless you know that your tank water is also soft and acidic, the Tetras that need that water should be avoided. Before you buy a Tetra that you are not sure about, look it up in your book. If it says that it needs a pH below 6.5 you should probably avoid it. While many beginning aquarists are tempted to simply adjust the pH of their water by buying little containers of chemicals in the pet store, do not give in to this temptation! Water chemistry is very complex and you can easily kill all your fish by trying it.

On the other hand, if your tap water is naturally soft and achieves a consistent acidic pH, there is no reason that you can’t try your hand at some of these fish.

Two very popular Tetras which need soft, acidic water are the Neon Tetra - Paracheirodon innesi and the Cardinal Tetra - Cheirodon axelrodi. These are quite attractive red and blue fish. The red line on the Cardinal runs from the head on back, while in the Neon it starts only in the belly region. But their attractiveness is their only advantage. Besides its water requirements the Neon has the added drawback that almost all of them are bred in the Far East in huge numbers with no regard to quality. Further, the raising ponds for the young fish are filled with medicines. The medicines keep diseases in check but as soon as the fish are shipped they begin to get sick. They die in huge numbers in the stores and in buyer’s home tanks. Probably less than 1 in 10 Neons lives for more than one month after being removed from the pond it was raised in. Further, those two or three tiny neons for a dollar at the local store can easily introduce a disease that kills all the fish in your tank.

Cardinals will have a greater chance of not dying immediately after purchase but even they will probably not live long in your home tank. They are wild caught in Brazil as adults so they may have lived most of their naturally short life span before you buy them.

Other Tetras which need acidic water include the Blue Neon Tetra - Hyphessobrycon simulans, the Flag Tetra - H. heterorhabdus, H. metae, the Loreto Tetra - H. loretoensis, the Black Phantom Tetra - Megalamphodus megalopterus, and the Red Phantom Tetra - M. sweglesi.

So what about those aquarists without acid water? There are plenty of hardy Tetras out there for beginners without special water. These include the distinctive Black or Black Skirt Tetra - Gymnocorymbus ternetzi, the brightly colored Glow Light Tetra - Hemigrammus erythrozonus, the radiant orange Jewel Tetra - Hyphessobrycon callistus, the Flame Tetra - H. flammeus, and the red-tailed Pristella - Pristella maxillaris, all of which grow to less than two inches long. Slightly larger Tetras include the Penguin Tetra - Thayeria obliqua and the closely related Hockey-stick Tetra - Th. boehlkei, both of which are easily recognized by the black lines originating in the lower half of their caudal (tail) fins and running forward, the shiny Diamond Tetra - Moenkhausia pittieri, and the beautiful, trident-tailed Emperor Tetra - N. palmeri. Finally, the only African Tetra frequently seen, the Congo Tetra - Phenacogrammus interruptus is a gorgeous fish which grows up to four inches long.

Cichlids

Cichlids, members of the family Cichlidae, come from Central and South America and Africa, with a few species found in Madagascar, the Middle East and into Asia. Cichlids are quite unlike any of the fish discussed so far. They are related to and resemble the Perch and Sunfish of US waters. For aquarists, cichlids pose four major problems: (1) Some need special water conditions, (2) some have specialized diets, (3) some get quite large (the largest up to 3′ long), and (4) all are territorial.Again, why bother? Because for those willing to take the challenge, the rewards can be great. If any fish can be said to be intelligent, Cichlids can. They display this in their everyday activities as well as in their specialized mating, breeding, and fry-raising activities. The fish mentioned in the previous sections all lay eggs and then ignore or even eat them! Cichlids, on the other hand, care for their eggs and young. It is said that one of the most rewarding sights an aquarist can see is parental Cichlids herding their fry around the tank and protecting them from all dangers. And, even if your Cichlids never breed, they will be more responsive to you than perhaps any other fish. Cichlids can be much more “pet-like” than you might think a fish could be.

If you do decide to take the Cichlid challenge, choosing your Cichlids can be difficult. Some can be added to your community tank and will do fine with the schooling fish talked about above. These include Curviceps - Aequidens (really Laetacara) curviceps, Dorsigers - Aequidens (again, really Laetacara) dorsiger, and the less frequently seen Nannacara anomala, all from South America, and Thomas’ Dwarf Cichlid - Anomalochromis thomasi from western Africa. Unlike the monster Cichlids, these fish stay small (3 1/2” is a good sized adult) and are relatively peaceful. Two or three may be placed in a 10 gallon tank and they should still all find places to live if there are rocks and other decorations in the tank.

Other Dwarf Cichlids you may see are the Ram - Papiliochromis (some books use Microgeophagus or Apistogramma) ramirezi, Apistos - Apistogramma species, and the Checkerboard Cichlid - Dicrossus filamentosus (referred to as Crenicara filamentosa in the books). These fish vary in their difficulty for keeping as aquarium fish, but all of them should be avoided by beginners.

Keyhole Cichlids - Aequidens (really Cleithracara) maronii, Festivums - Cichlasoma (really Mesonauta) festivus, and Angelfish - Pterophyllum scalare can be good fish for the relative novice, but only if healthy specimens can be found and this is often not easy. For this reason, small Keyholes and Festivums should not be purchased. Adults of these two species are generally better choices; still, one should look the fish over carefully and not buy them until they have been in the store tanks for at least a week. Similarly, for the very popular Angelfish, one needs to be very careful when buying them. Before you buy, ask the salesperson to tell you where the store gets its Angels. If the salesperson doesn’t know, won’t tell you, or says that they come from “the wholesaler” (and who knows where before that?) don’t buy them. If you are told that they come from a local breeder then you have at least a chance of getting healthy fish. Also, Angels should be kept in tanks both taller and longer than a 10 gallon aquarium. Keyholes, Festivums, and Angels are all shy fish and should be provided with cover — preferably a planted tank.

Discus, like Angels, need tanks higher and longer than 10 gallon tanks. Their specialized needs do not stop there, however, and beginners should shy away from these difficult and demanding fish.

At the other end of the difficultly scale, a very good choice, especially for those with a 20 gallon or larger aquarium, is the “Jurupari” - Satanoperca leucosticta (formerly referred to in the hobby as Geophagus jurupari). It does get large (up to a foot), but it grows very slowly and may still be less than six inches long when several years old. It is a very peaceful Cichlid which will help to clean your tank by sifting through the gravel for uneaten food. A similar fish, Geophagus surinamensis, is also a good choice.

Kribs or “Kribensis” - Pelvicachromis pulcher are a widely seen West African Cichlid that will do well with the larger schooling fish and should be kept in a twenty gallon or larger tank. Male Kribs grow to be 4″ long and females stay a bit smaller.

Most of the remaining cichlids which are commonly available are too aggressive and/or grow too large for the beginning aquarist to effectively deal with. This includes the very popular Oscar - Astronotus ocellatus which grows rapidly to over a foot, is opportunistically piscivorous, and is a very messy species. If the aquarist is truly interested in keeping more cichlids than those recommended above, she or he should be prepared to set up special, separate (and probably larger) tanks for these fish and to read more extensively on cichlids before buying them.

Anabantids

Anabantids are another group of fishes that are quite different from those already discussed. Distantly related to Cichlids and Perch, Anabantids are found in Africa and Asia. Members of the families Anabantidae, Belontiidae, Helostomatidae, and Osphronemidae, Anabantids are also referred to as the “labyrinth fishes”. This is due to a special breathing organ referred to as the labyrinth organ which is essentially a maze of tunnels near the fish’s gills. Labyrinth fish gulp air at the surface of the water and absorb it through the labyrinth organ, allowing them to live in water with too little oxygen to support fish which only breath through their gills. Some Anabantids can survive out of water for several hours breathing only through their labyrinths, as long as they stay moist. Anabas testudineus, known as the Climbing Perch, is said to be able to climb trees and to live out of water for up to two days.As well as giving aquarists some additional choices for community-tank fish, Anabantids offer some unique options to fish keepers as well as presenting a few problems. Because some Anabantids are able to withstand cooler temperatures, and because of their ability to survive in water with very low oxygen, these fishes can be kept in tanks or bowls without heaters or filtration. On the other hand, some Anabantids (particularly males of some species) are very territorial and some grow quite large.

Breeding Anabantids can be quite rewarding. Some species build nests out of bubbles into which they place their eggs while others, like some Cichlids, are mouthbrooders.

The most commonly seen Anabantid is probably the Betta or Siamese Fighting Fish (which is generally said to be Betta splendens but is probably a crossbreed). Artificial color varieties with red, blue, green, purple, and many other colors in various combinations are widely available. Males are bred to have very large fins and both sexes are seen with double tails. Siamese Fighting Fish generally make poor choices for the community tank for two reasons. First, as their name would imply, they are very territorial. The aggression is greatest between two males, but can be directed towards any fish that looks to the Betta too much like another Betta. Second, their long fins make easy targets for many fish such as Barbs. Siamese Fighting Fish can be kept alone in bowls (the larger the better) or tanks without filtration as long as frequent partial water changes are done. They do need warm temperatures, however, and are sensitive to temperature changes, so a constant heat supply is needed if the room is less than about 75F. Also, due to poor breeding, many Siamese Fighting Fish are not very healthy. A 3″ male would be a large adult; females stay smaller.

A better choice for keeping alone in a bowl or small tank is the Paradise Fish - Macropodus opercularis. These are much hardier fish than the Fighters and can withstand temperatures down to 60F. They may jump, however, so the tank should be covered to be safe. Also, like Siamese Fighting Fish, male Paradise Fish can be extremely territorial towards one another. Paradise Fish may get up to 4″ long.

Another very commonly seen Anabantid is the Blue or Three-Spot Gourami - Trichogaster trichopterus. Gold, Silver, and Cosby Gouramies are also widely available and are simply artificial color varieties of the Blue Gourami. Blue Gouramies can get up to 6″ long. They are not as aggressive as Fighters or Paradise Fish, but more than one in a small tank may lead to constant (if not overly deadly) chasing. They will do well in a tank with larger schooling fishes. Similar, though slightly smaller species include the Banded or Giant Gourami - Colisa fasciata (which is only a giant compared to the similarly colored Dwarf Gourami described below), the Thick-lipped Gourami - Colisa labiosa and the somewhat less aggressive Pearl Gourami - Trichogaster leeri and Moonlight Gourami - T. microlepis. The Kissing Gourami - Helostoma temmincki grows larger (up to 12″) but makes a good fish for beginners with larger tanks. It is peaceful, though males will contest with one another by pressing their lips together and pushing - the so-called “kissing” from which the common name derives. Most Kissing Gouramies seen will be of the Pink variety.

Small Gouramies, only growing to 2″ or so in length, are also available. These include the Dwarf Gourami - Colisa lalia, the Honey Gourami - C. chuna, and the Sunset Dwarf Gourami (probably a cross between C. lalia and C. chuna). In theory, these would all be good fish for the community aquarium. In practice, these fish are often the victims of poor breeding practices in the Far East (like so many others described before) and many are even treated with hormones before they are shipped to make them appear brighter in the store tanks. A good rule of thumb is, “If it looks too good to be true, it probably is.”

Although harder to find, Anabantids which have had less human interference with their reproduction are generally better choices. Look for the Mouthbrooding Betta - Betta pugnax, the Licorice Gourami - Parosphromenus deissneri, the Spike-Tailed Paradise Fish - Pseudosphromenus cupanus, the Croaking Gourami - Trichopsis vittatus, and the Dwarf Croaking Gourami - T. pumilus, which range in size from 1″ to 4″. Do not buy Chocolate Gouramies - Sphaerichthys osphromenoides which are quite delicate, or the true Giant Gouramies - Osphronemus spp. which grow quickly to well over two feet long.

Livebearers

The family Poeciliidae contains Guppies, Mollies, Platies, and many other fishes. While these fish are often thought of as beginners’ fish they have been intentionally left off the list until now in order to make a point. The reasons these fish are often sold to beginners are that they are cheap, brightly colored, and have a general reputation among non-aquarists as easy fish. Notably absent from this list is any real suitability for keeping by beginners. For one thing, many livebearers need high level of salt in their water to be healthy - making them incompatible with many other aquarium fish. Many common livebearers also are overbred, resulting in fish not nearly as healthy as those kept by aquarists of previous generations (or by the authors of most books). Some are not even able to reproduce without human intervention. Finally, due to their low market price, they are generally not well cared for and may carry diseases.Poeciliids, as they are also called, come from the Americas, primarily Central America. They are called “livebearers” (as opposed to “egg-layers”, as all the previously discussed fish have been) because the eggs are fertilized within the female and the fry do not appear until the eggs have hatched. There are also livebearers from other families in which the details of reproduction vary.

The well-known Guppy can be found in a number of colors and with as many as 12 different artificial tail varieties. Also available is the closest thing that you may find to the wild Guppy - Poecilia reticulata: “feeder Guppies” which are not bred for color. The fancy strains tend to be fragile while common Guppies often carry diseases. Guppies should be kept in water with at least one teaspoon of salt per five gallons of water.

Common Mollies are the Black Molly (which was derived from the Marled Molly - Poecilia sphenops) and the Sail-Fin Molly - Poecilia velifera (of which there are also several color varieties available). Black Mollies need at least one teaspoon of salt per five gallons of water to keep them healthy and prevent the outbreak of “ich” (Ichthyophthirius multifiliis, a parasite commonly seen in aquaria) while Sail-Fin Mollies need at least three times this amount. Sail-Fins grow to 6″ while Black Mollies stay less than 3″.

Closely related, Swordtails - Xiphophorus helleri and Platies - Xiphophorus maculatus are also popular fish. A number of color and finnage varieties are available of each with some of the Platies also referred to as “Moons”. These fish need at least a teaspoon of salt per 5 gallons of water to be healthy. Some varieties are susceptible to various maladies (Tuxedo Swords often get tumors, for instance) and as with so many other fish the naturally colored fish are probably your best bets. “Green Swords” (which are really multi-colored) are naturally colored X. helleri, but unfortunately wild morphs of Platies are not often seen. The Variegated Platy - Xiphophorus variatus is sometimes seen, however, and fills this role nicely.

Origins of diseases
The origin of a disease can be external:
- adding in the aquarium a stressed fish during the transport from a country to another, or from a pet shop to home; a disease can occur and it can spread to other aquarium fish too
- adding a disease carrier fish or a sick fish
- adding polluted water from nature
- accidentally adding toxic substances – smoke and others
Of course, you have to be careful in order to avoid all these situations. The diseases can also have internal origins, because of the perturbation of the general equilibrium from the aquarium, which activates the diseases to carrier fish:
- the decrease of the temperature, or temperature shock, sudden variations of temperature in both senses (+ or -), induced by an injury at the heating system
- the decrease of the oxygen level
- over flow of nitrogen substances, caused by an injury to the filtration system of by the big number of fish in the aquarium
- the general quality of the aquarium water
- wounds suffered during a fight or during spawn, or caused by hitting the décor
- bad feeding or incorrect equilibrated feeding
- the presence of plants under decomposing

The prevention of diseases
It’s better to prevent a disease than to heal it, it’s an old saying valiant in aquariums too… Prevention of diseases means a daily observation on the fish and aquarium environment, some knowledge being needed. The best prevention way is maintaining the aquarium equilibrium as better as possible.

Diseases and their treatment
Globally, there are 2 kinds of aquarium fish diseases: infectious diseases and non infectious diseases. The first ones are induced by microorganisms, like bacteria, fungus or viruses carried by aquarium fish. The activation factors are well known: stress, miss alimentation, decrease of the temperature. Some pathogen organisms have a mixed life: a part in the fish body and another part in the aquarium environment.

Non infectious diseases are not induced by pathogen organisms, but by the polluted environment and lack of needed substances, you’ll have to avoid the mixture of medicine or their over administration, because they are useless and in most cases bad for the fish. You’ll have to respect the period of treatment even if the symptoms disappear. Anyway, you’ll have to focus on the fish’s health for its entire life. During the treatment of a disease, the feeding must be equilibrated and it must contain natural elements. After healing, you’ll have to administrate vitamins and minerals in order to make it stronger and improve its general condition.

Diets and food needs

By their diet, there are 3 kinds of fish:
- carnivorous fish, which eat insects, worms, shell-fish and other small fish
- herbivorous fish, which eat vegetables (plants or algae)
- omnivorous fish, which have a much diversified diet because they eat both vegetal and animal food.

It`s hard to define the diet. In nature, fish eat what they can find. That way the herbivorous fish eat sometimes small insects which can be found between the plants. The carnivorous fish especially need proteins and lipids, the herbivorous ones need especially glucose and the omnivorous fish need all 3 kinds: proteins, lipids and glucose.

These 3 diets can be found at aquarium fish too, with some exceptions. You shouldn`t forget about the vitamins and minerals which should be provided by a healthy diet. A diversified food provides the necessary elements for a good growth and breed, and also it helps preventing the diseases. In conclusion, diversified food helps the equilibrium from the aquarium.

Intake

There is a temptation of over feed the fish, resulting fat ones. This way, the risk of polluting the environment increases (a fish eating a lot will produce a proportional quantity of excrements).

An adult fish can only eat 1-2% quantity of its body weight in one day, and double if it is young. The plants are very light, they don`t present the risk of over feed, and the problem is only with the other foods. It`s recommended to program the food over the day; 2 times for adults and more times for young ones.

Fish can easily handle short periods of hunger, because of the probability that in their natural environment could be the same conditions of less food. Some aquarium fish breeder set a day in the week when they don`t feed their fish, just in case of over feed in the other days. Young offspring can suffer if they are not fed, causing them low development.

Artificial food

It`s about dry food sold out in aquaria markets/shops. They have diversified a lot in the last twenty years. Nowadays there are lots of food sets for each class of fish: fry and adults, freshwater fish and saltwater fish, etc… These foods are rich in proteins (40 to 50%) and have different forms: dehydrated foods (the most common), tablets or met feather shot. The dry food floats for a while, and then it submerges facilitating the feeding of surface and middle depth fish. Met feather shot submerge faster facilitating the feeding of middle depth and bottom fish. There are more sizes for the foods, depending on the size of the mouth. Artificial food is fragile; it degrades if it is kept in inadequate spaces. They must be kept in dry and darken spaces and it`s better to buy a medium size box if we have few fish…

Some of the tropical fish breeders feed their fish with trout food which they get from piscicultural farms. These foods, rich in lipids, favor a fast grow of the trouts which are breed for human feeding , but which is not the essential scope of aquaria. Even if these foods contain pigments which are used to color the skin of trout, the aquarium fish breeders who used them say they didn`t notice any coloration of their fish skin. Anyway, this kind of feeding is economic at industrial scale or for garden ponds.

Sometimes, the marine fish permanently or a certain period, refuse the artificial food after they are introduced in aquariums. A solution for this problem is administrating both artificial and natural food and, in time, reduce the quantity of natural food.

Frozen food

Fish can be fed with frozen shrimps, fish, worms, plankton after they are selected and cleaned. Their nutritional value is very high because the freezing doesn`t change their composition. They are kept in the refrigerator and they don`t need refreeze after defreeze. This kind of food is quite expensive in comparison with other kinds of food.

Home made food

In this last category, we have foods which can be administrated fresh or after freezing and defreeze. You have to avoid red meat and too greasy meats. Beast heart, rich in blood and lipids, will only be used for big fish. White meats are preferred: chicken, turkey, ham. From marine, we can use white fish, mollusks, shells, shrimps, which we can buy as tinned. Vegetal foods are needed for herbivorous fish because these aliments are rich in vitamins and minerals. We`ll use salad or spinach which has to be boiled for a few minutes.

Vitamins

Vitamins are very important for fish feeding as for human feeding. They have a use in skeleton developing; they help the growing and strengthen the resistance to diseases. A tropical fish which suffers of a vitamin lack will weaken, and this thing isn`t visible at the beginning. The vitamins degrade under the action of heat, oxygen and light. That`s why the main intake will be made by fresh foods, living food or frozen foods.

Dung worms

Actually, they are not worms but aquatic larva of different mosquito species. They are known as fishing bait. Contrary to their name, they don`t live in dung but in the water from areas which are rich in organic materials. You don`t have to look for them because you can find them in aquaria markets/stores. They are kept for a few days in newspaper wet paper in the fridge. They are good foods, rich in proteins, much appreciated and looked for by all aquarium fish.

Tubifex worms

These worms are taken from ooze which is rich in organic materials. Some tropical fish breeders consider that these worms represent a risk for the aquarium, because they can bring in unwanted bacteria. This risk remains limited because there haven`t been reported any severe accidents. The worms which can be found in shops are kept in fresh water for a few days at low temperatures in the fridge, but it`s very important to change the water daily in order to avoid their degradation. They are much appreciated by most of the aquarium fish.

Shrimps

In well oxygenated freshwaters there are some small shrimps with a size of 1-2 cm which swim laterally. These are the freshwater shrimps. Rarely are they sold alive, but they can be found in aquaria shops. Even you can catch them and give to the fish which appreciate them very much. There are some saltwater shrimps in the Romanian part of the Black Sea, which are appreciated especially by saltwater fish. Sometimes, they are sold at the fishing stores from the sea side. The ones who live in those are can catch them and keep them in aquariums with oxygenated saltwater. These two kinds of shrimps can be boiled and rinsed out with fresh water and after that you can mix them in order to obtain a home made food.

Small fish

For feeding marine fish, which refuse artificial foods, or big freshwater fish, we can use small fish. For doing this, some fish breeders with better experience breed prolific species, which reproduction is done easily in aquariums (Poeciliidae for examp…)

Plankton foods

Freshwater planktons or saltwater planktons contain multiple organisms which can hardly be seen (0.1-1 cm), but interesting for feeding our aquarium fish, especially the fry. In natural environment there is a big quantity, but there is a risk of bringing microorganisms that induce diseases in the aquarium. Some planktons can be found for sale in aquaria shops/markets.

Breeding baby brine shrimp (Artemia salina)

Dry eggs (called cysts) can be found in aquaria shops/markets. They must be kept in dry and dark places. In order to hatch, we`ll have to prepare saltwater with a temperature of 25° C, 3.5% salt, a density of 1023 g/l. The water can be natural, with special salt for aquaria, or you can use normal salt (easier if you don`t have marine aquariums). The water can be colder and less salty (20° C and 2% salt, density 1014), but the percentage of hatching is lower (50-60% in comparison with 80-90% if the first conditions are realized). We can use any plastic or glass tank with a small volume, though there are specialized tanks in aquaria shops. The eggs must be kept in calm water for a few minutes in order to re hydrate them. Knowing that 250.000 eggs weigh about 1 g, a small quantity is enough for breeding artemias for a generation of fry. The water is agitated with an air pomp which generates bubbles.

A big pressure will throw the eggs on the laterals making their hatching impossible. The hatching takes place in 24-36 hours at a temperature of 25° C, and 48 hours at a temperature of 20° C. At this moment you`ll have to stop the air pomp. The shells will float, the unhatched eggs will submerge and the artemias will swim at medium depth. In order to give the artemias to fish we can put all the artemias together using a pocket lantern. Artemias can live in freshwater just a few minutes. In the first day artemia doesn`t eat. You can feed your artemias with specialized food from aquaria shops and you can have adult artemias.

Paramecium

They are unicellular microscopic organisms. They represent a small quantity in the aquarium. Riccia, a floating plant, permits their developing because they can find food on the plant`s leaves. You can also get paramecium if you put some old aquarium water in a tank and introduce there salad leaf or paddy rice (unpeeled rice available in specialized shops from larger cities). The paramecium represents the perfect food for the fry.

A marvel food for fry

It`s about the yolk of egg, boiled, firm and put in a glass of water. Some micro particles form, which are get through a sifter which keeps the big particles. This soup is given to fry making sure we don`t pollute the aquarium. The yolk of egg, rich in proteins and lipids, can supply other foods. This food is very nourishing and it is indicated to all tropical fish breeders.

What can we do if a fish doesn`t eat?!

Sometimes it may happen that a fish refuses the food or can`t eat it. We have to search and cross out the cause. A new fish, recently introduced in the aquarium rarely feeds from the first day: it`s a normal fact because it feels lost in the new environment. The small species and the less active fish are dominated by big and active fish while wee feed them. In this case we have to feed them separately, better with small living food, after we distract the other fish attention with other foods.

A fish can refuse the food because it has a disease, which can be easily remarked. In this case we have to put the fish in a separate tank and feed it with lot of fresh living food.

Breeding freshwater fish in aquariums requests a minimum of knowledge about the anatomy and biology of the species you want to breed. The next few information, available for everyone, will allow you to keep healthy aquarium fish in the best conditions, will allow you to feed them right to guarantee their rising, facilitate their reproduction, with other words it will help you understand freshwater fish better.

The food must provide freshwater fish the necesary elements for biosynthesing proteins for thei body and the energy indispensable for their survival (this is the function of proteins, glucose and lipids). Feeding a freshwater fish means providing it a good develope, facilitate its reproduction and help it fight against freshwater fish diseases. The quality and quantity of food are 2 important terms; you have to avoid the supercharge and you also have to diversify the food.In the temperate zones of the globe, the reproduction of fish depends on the season, namely it depends on the temperature. There is a single season to spawn, in the time when the fish breeds. In tropical environment, where the temperature variations are less important, the breeding of fish takes place depending on other factors, mostly on rains. Aquarium fish are able to breed more times a year, sometimes at intervals shorter than a month.

You must learn to detect the symptoms of diseases and mostly to get use with the maintenance and hygiene standards, in order to prevent any disease. An exotic fish can be sick, but also a disease carrier without suffering the symptoms. The disease will activate in certain conditions and will spread to other aquarium fish.

Most of the times we first buy an aquarium and only then we think where we should place it. The disposal place of the aquarium must be carefully selected, because after you mount the aquarium, it is very hard to change its position. While moving it you can even break the aquarium. That’s why it has to be empty, with no fish and no plants and moved in another place. Choosing the place for an aquarium is very hard. For example, if we place a small aquarium close to a door or window, the temperature variations will be high regardless of the heater. Then the fish diseases may occur. If it is placed in the kitchen, or in places where you work with volatile substances - oil fumes – will produce the tuck the valve of the vibrator or may produce oil shell on the aquarium water surface.
Another element that we should consider in placing the aquarium is represented by the light. If we place the aquarium where it receives south light, this thing won’t allow the breeding of green and blue algae but the only plants that could grow are Cryptocoryne which need a low quantity of light. A placement near a window which receives north light will create an over flow of green and blue algae. Neither the west orientated windows give too much light, that’s why the recommended places are near windows that receive east light.
There are 2 ways for placing the aquarium in order to be able to use the solar light from windows:
- aquarium disposal on the opposite wall
- aquarium disposal on a wall perpendicular to the one with the window
In both cases the light is received by the front face of the aquarium, assuring a good illumination for both small and big plants. Placing the aquarium like that is in the benefit of fish too because they can receive good light and they will be more active and will show their real colors

The pH measure water`s acidity or alkalinity. 7 means neutrality; under this value this water is acid and, up from this, basic. An acid water doesn`t contain dangerous acids; in forest`s rivers it fills with organic materials and acids provided by the decomposed plants (humus); it can be recognized by it`s light yellow color. Generally, aquatic`s lift is possible only between 5 and 9. These extreme values may be obtained rarely in the aquarium, where the pH varies between 6 and 8, depending on water`s type. In aquarium`s science books is talked about an acid water when the pH varies between 6 and 6.8 and about a basic one between 7.2 and 8.
Between 6.8 and 7.2 it is consider a neutral water. These changing values of the pH are because of the biological alternations. The carbon dioxide produce by creatures when it`s night makes water to became more acid and the pH is decrease slowly. In time when it is absorbed by the plants the value is increasing again. A weak vary is considered normal but big difference show that there are problems. The pH is a good indicator of aquarium`s equilibrium, and it is a constantly measure indicator. With the help of a colored indicator we are able to compare the obtained colors on a calorimetric scale; there are electronic pH-meters too.

pH adjusting
Water doesn`t certainly have a likeable pH for the fishes. Furthermore, when an aquarium is functioning the pH can slowly but regularly increases or decrease. Some products can help pH adjusting but there are different ways which help us to do the same thing:
- if the pH is too high we can add a more acid water, limit water`s agitation, or filter the water with the help of the peat which will eliminate some acids.
- if the ph is too low we can add basic water, we care grow water`s agitation (which help the removing of carbon dioxide or we can filter the water with a calcareous material.

While the air contains 20% oxygen, the most oxygenate waters rarely contain 1% oxygen. The fish have some organs, branches, allowing them to extract the most oxygen dissolved in water. The oxygen is also used in plants respiration and other invisible creatures from the aquarium, such as bacteria. These convert the organic compost resulted from organisms (excrements, food, other); the chemical reactions for this conversions also require oxygen use.
The water oxygen results from dissolving of air oxygen, favored by water motion: wind, current, flow. The water is more oxygenate if it is tumultuous. The plants also produce oxygen by photosynthesis, but only while daylight. The maximum quantity of oxygen in water depends on the temperature; as the temperature increases the oxygen level decreases (at 25° C there is 18% less oxygen as at 15° C). The oxygen level is measured in mg/l and the dosage is quite delicate. The most oxygenate waters contain about 8-10 mg/l oxygen, and the most pauper ones 2 mg/l. In aquariums, the oxygen level is usually at maximum. The problems appear only if the general balance is not respected, (fish overpopulation and few plants) or when the materials don`t work (interruption of energy or oblivion).
The carbon dioxide results from the fish, plants and bacteria respiration. The motion of water, which increases the oxygen level, decreases the carbon dioxide level, which goes in the atmospheric air. In aquariums, you can rarely find important quantity of dioxide, which could affect the plants. In day time, he plants absorb the dioxide and use it for photosynthesis in order to produce oxygen, indispensable to aquatic life. A permanent equilibrium should be settled between oxygen, dioxide, fish and plants. This equilibrium changes during night when the plants stop providing oxygen. The carbon dioxide is one of the important factors which affect the pH.

An important water parameter for the aquatic life, influencing the quantity of oxygen but also lots of very important factors which contribute to developing life in aquariums. Otherwise the internal temperature of the mammals which is constant, the temperature of aquarium fish and other creatures varies depending on the aquarium water temperature. They can only survive at certain temperatures, some fish species being sensible to this water parameter more than others.
The tropical freshwater is characterized by lower temperature variations in comparison with the temperate water such as the ones in France; their amplitude is between 20 and 30 ° C. Local, the tropical forest shade decreases the temperature of the water, but the water temperature increases in the stagnant ones under the direct influence of the sun. An aquarium water temperature of 25° C is mostly recommended and variations of 1-2° C are insignificant. For short periods of time (less than 24 hours) aquarium fish can survive to higher variations, instead, for longer periods, their metabolism (the general performance of their body) risks to be highly perturbed, death can occur in shorter or longer periods of time. Also, in most cases, low temperatures favor disease developing.

This closed envitonment existing in an aquarium can help you understand some ecologic phenomenons and it represents a great start in this science which came into sight just a century ago. It doesn’t reflect only to the human being in its environment, but reflects all the mecanisms that regulate the relations between people and their environment. Even if lots of freshwater fish breeder, mostly beginners, remain izolated, it is verry profitable to make contact with aquarium clubs and associations. This way, the aquarium becomes a small world where we recognise the interrelations between ecologic factors at global level, relations that were able to explain the dependings between creatures. Also taking care of an aquarium, or better, mentaining the equilibrum in an aquarium, can be considered a task that a child should assume, being conscious of the responsability. Many parents buy a pet to their kid in order to develope its responsability sense, but only few pets are so suitable as aquarium fish. For example, a dog requests taking it outside and the child may be in danger without the supervision of parents, but the aquarium fish are completely harmless (at least the freshwater ones).
Without water there would be no life on our planet. But neither a too clean water is suitable for creatures developing. Life developing depends on the elements that water contains. The life and aquarium fish and plants breeding request some knowledge about water parameters, environment element mostly not known as life environment. In the aquarium the same phenomenons take place as in nature, of course at a lower level, that’s why the most important element’s cycles are present in aquariums too: carbon, nitrogen, oxigen… the quality of aquarium water being very influenced by the quantity of organic compound determined by the presence of aquarium creatures.

Aquarium models
There are plenty forms of aquariums susceptible of suiting with the interior of any house. Traditionally, most of the aquariums have a rectangular shape, more or less prolonged nowadays the aquariums are more high than long cubic or panoramic, especially adapted for certain emplacements. The main model is formed by a tank with a table over it. You can also adapt an illumination system. Then you can find a suitable model for this system with an exterior decoration made from a band of a certain size around the base and the superior part in order to dissimulate the water level.
This kind of aquarium can be commercialized alone or with a support. Sometimes it is equipped with a filtration system. Then we can find the more sophisticated aquarium models, integrated in a piece of furniture. In general the aquarium is represented by a tank and an illumination gallery, containing wood plaques for hiding the pomp and other materials. The entire aquarium is covered by a piece of furniture as a decoration, and only 3 faces can be seen.

Aquarium materials
Most of the commercialized aquariums are made from glass glued with silicone. Using these materials is recommended to a volume of max 500 liters, rarely over fulfilled in commerce. The neutrality of these materials and the facility of gluing them make them easy for the use of any amateur who can make his own aquarium.
For bigger volumes you can use resin and polyester, only the frontal face of the aquarium being made from glass. They are made from cement too, but these 2 last types of aquariums can only be seen in public spaces. The Plexiglas, light material but which cracks when curved, is rarely used for curbed shapes. There are also some small plastic tanks used for breeding or as a hospital aquarium.

Aquarium dimensions
The most harmonious form is obtained when the length is equal with the height multiplied with 1.5-2.5. The height will be just a little longer than the width. These proportions can be respected till a length of 1.5 meters. Over this dimension there will be an impossibility of keeping the proportions, because the height must not excel 0.5 meters.
The use of too tight aquariums is not recommended. Indeed the optic effect makes an aquarium look smaller with 1/3 when it`s full with water, making an undesired image. Though it can be interesting if placed on furniture with small dimensions; on a fireplace or a separator wall between two rooms. We`ll have to use a solid support, because an active aquarium weights quite enough, to the weight of the tank you add the weight of the water and the décor.