Tropical Aquarium Fish

Every fish breeder dreams to having an aquarium with discuses, to being able of breeding even reproducing discuses. This superb fish, from every point of view: shape, size, color, behavior, represents the top of pride in our aquariums, pride top which most of times we can`t reach. For being able to breed this fish, we need more years aquaria experience, and theoretical knowledge that most of us don`t have. It`s not enough to have an aquarium, water, aquatic plants, a vibrator and maybe a heater in order to buy two or four discuses and claim that we are discus breeders. We can`t say we are discus breeders even if we have discuses in our aquariums The literature about Symphysodon discus has improved in the last 10-15 years, but most of the aquarium fish breeders don`t have access to it, same thing happening with other aquarium fish species too. In Romania there are some breeders, also in Bucharest, who reproduce this fish regularly, which used to have a methodic price before the revolution (anyone could afford buying it). But let`s get back to the requests of breeding discuses, requests that are very important to fulfill. Of course we need an aquarium (but not any kind of aquarium), water (but not any kind of water) and temperature (but not as for other aquarium fish species, discuses need a constant temperature maintained at 28-31° C using a thermostat). Why do the discuses need such a special care, different than any other species? What are the differences between discuses and other aquarium fish, even those from the same natural habit?

The discus is a fish which has a continuity of only 50-60 years in our aquariums; I`m talking about the wild discuses. The reproduction is not as hard as the fulfill of the needed conditions. These conditions are the same as in the natural environment. The fry care is a big difference between discuses and any other aquarium fish. Everything is special with discuses: from food to water, spawning, diseases (some diseases are specific only for discuses). So let`s see what we know about discuses.

There are two ways to go about obtaining a breeding pair of discus. The most common is to buy a group of young discus and grow them up together. For a good chance of getting a pair, at least six discus must be purchased, hopefully from a few different sources so as to get some genetic diversity in the breeding program. These fish are then housed together until pairs can be determined. When two discus pair off they will defend a territory in the aquarium against all of their other tank mates. When this behaviour is observed it is time for the breeder to move the “newlyweds” to an aquarium of their own. The second way to obtain a breeding pair is to go out and buy one. This is a more expensive route, since proven pairs sell for several hundred dollars, but it will yield the fastest results.

Regardless of how you get your pair, you will need an aquarium set up for them with the objective of breeding in mind. A twenty or twenty-seven gallon tall tank is ideal for these “tall” fish. The bottom is left bare, so that removing any left over food and other debris is easy. The only decor required by the pair is a spawning surface. Discus lay their eggs in the same manner as angels, and so a vertical surface should be provided for them to deposit their eggs on. I use an inverted ceramic flower pot, but the discus aren’t picky and will use whatever surface is available. A potted plant or two can be added to the breeding tank if so desired, and will provide some shelter for the pair, but this is not essential. As far as filtration goes, a sponge filter should be used to handle the biological load, and an outside power filter to pick up any debris that may be in the water. I also like to add a mesh bag of peat moss in the power filter so as to better replicate the natural water conditions that discus come from.

This brings us to the first and most important secret you will need to know if you are going to have any success breeding discus. This is the secret of water quality. Discus come from the warm, soft, acidic waters of the Amazon River. It’s no surprise then that discus thrive when these conditions are replicated in the home aquarium. For both general maintenance and breeding of discus the pH should be kept at 6.5, and the temperature around 86 F. Any alterations that need to be made to the water chemistry should always be done prior to the water being added to the tank. For general maintenance water changes should be performed weekly. However in the breeding tank, a small water change should be done every day, or every second day. Frequent water changes increase appetite and promote mating activity in discus. It’s no coincidence that discus will often spawn after a water change.

The second secret is related to the first, and this is the secret of food. If good water quality is maintained the discus will have large appetites and should greedily accept any food offered to them. My discus get fed only frozen bloodworms. The reason for this is that they are clean and convenient to use. Other foods that can be used include beef heart, Tetra Color Bits, frozen or live brine shrimp, and live white worms. If feeding beef heart, one must be careful that none is left over because it will foul the water very quickly. Live tubifex or black worms should never be fed to discus at any time, as I can guarantee that they will introduce parasites to the tank.

Once these two secrets are mastered, breeding discus is a cinch. The breeding pair will lay eggs as often as every week, as many as fifteen times. They will usually go through two of these spawning cycles in a year. The eggs take 48 hours to hatch , and are free-swimming another 72 hours later. Immediately upon becoming free-swimming the fry will move to their parents’ sides, and start feeding off the mucous secretion that is produced by the parents during this time. The fry will feed off their parents’ sides for as long as you leave them together, but they should be offered newly hatched brine shrimp after being free-swimming for five days.

In aquaria Xiphophorus maculata is known as platy. Their natural environment is in Mexico and Guatemala. The body is relative prolonged, with prolonged back and abdomen. There also are some varieties with high back and stumpy body. The dorsal fin has 9-10 rays, being relative small. There are some veil forms with a very prolonged dorsal fin. The male can reach 4 cm length and the female 6 cm. Even in nature, there are lots of coloration varieties, and in aquariums, due to selections, they are even more.

At the main platy variety, the scruff and the back area are dark olive, it has blue flanks. The laterals have dark colored transversal lines, the abdomen is white and the fins are transparent. On the base of the tail black spots can appear with different brown, red, blue drawings. As coloration varieties there are: golden platy, red platy, wagteil (red body with black tail and fins), tuxeto platy (black and shining scalds on a red or green background). In USA, Gordon obtained a variety called blooding heart which has the neck and the pectoral area colored in a bloody red and the rest of the body is white. The optimal temperature for breeding is 20-25° C. They are viviparous fish; females give birth to up to 100 living fry depending on the size of the female.

Xiphophorus helleri is spread in Central America, from Guatemala to north of Mexico. The main variety is colored in green, the so called green xipho, but due to repeated selections there are plenty of color varieties: red with black tail xipho, read with red eyes xipho, albino xipho, simpson xipho (with a prolonged dorsal fin), tuxeto (with a black longitudinal line), black xipho (from the tuxeto variety, which line coveres the entire lateral part of the body except the fins which remain transparent), berliner xipho (with plenty of black spots on the red background of the body), veiled xipho (with very prolonged paired and unpaired fins).

The female can reach 12 cm length, and the male is a little smaller. The sexual difference is obvious. The male has a modified anal fin, which is transformed into a sexual organ called gonopodium. At veil forms, the gonopodium is very large and the males are `sexual useless`. Another sexual difference is at the caudal fin. The base rays of the male`s anal fin are transformed in a sward; this gives the name of sword fish. There is a very interesting aspect related to sexual differences and sexes proportions. It`s about the reversibility of sexe and the sexe proportions at spawning. At a certain moment, a strong and well developed female changes the conformation of her body. The gonopodium and the sward appear and she becomes a male. This phenomenon can also take place at other viviparous species, like Xiphophorus maculata. Because of some external factors (pH etc) fisiological changes take place and the female transforms into a male. It is a reversible change, a false male like this can change back to female being able to give birth to fry.

Poecilia reticulata is the famous guppy, the most popular aquarium fish. In the natural environment, there are lots of guppy varieties as both body shape and coloration. In aquariums, due to repeated selections we gave even more than in nature. For guppy fish, there are international standards because a lot of contests are organized having this fish as a subject. The male has a more prolonged body, while the female`s is more compact, but the peduncle is more oblate on the flanks. It is very hard to describe a guppy male from the coloration point of view. Typically it has large spots, dark colored, on both body and fins which edges are shining. The female is less colored, she`s yellow-green, right before the anal area we can see the genital spot. The edges of the scalds are dark colored, giving the impression that they are coated by a netting; that`s the origin of the `reticulata` name.

They are spread in a large area, in South America, northern than Amazon, as well as in Trinidad and Barbados islands. The optimal temperature is about 22-24° C. Guppies eat almost anything, both living and dry food. They are viviparous fish, the females give birth to 20-100 fry at every 4 weeks.

It is a specie similar to Poecilia latipinna. These fish are spread in Yucatan peninsula (Mexico), where it lives in freshwaters. This specie also needs a salt add in the water of the aquarium, same one spoon with salt at every 4 liters of water. The dorsal fin of the male is very large. The male can reach 15 cm length and the female is larger, but in aquariums they remain smaller.The flanks of the mail are blue-green or olive, with lots of small spots silvery green to dark blue, between these spots they have longitudinal lines colored in blue-green. These lines can reach the base of the tail. In the abdominal fins area they have 3-4 transversal lines, short and dark colored. The abdominal area is colored in blue or orange. On the tail and dorsal fin, it has small pearly spots, with a dorsal fin hem colored in brown-orange or black. The female has the flanks colored in bleu-green, with small dark colored spots. The fins are transparent or they may have a dark colored drawing. This specie also has lots of color varieties. Some of them are: black or spotted with the dorsal fin hem-stitched in brown-red or orange. Rarely, there are some albino varieties. It`s recommended to cover the aquarium with a lid because they are likely to jump out of the water.

From the aquarium fish, goldfish have one of the longest life period, being able to reach ages of 18 years. It`s possible that the goldfish we know to be native from the Carassius carassius European specie or from Carassius auratus Asian specie. The name comes from old Greek. It`s a carp`s relative, the difference between the 2 species is that goldfish don`t have mustaches. Carassius auratus specie comes from Carassius auratus gibelio specie, the difference between them is at coloration, scales and fins. Carassius auratus is the first which was brought to Europe 300 years ago, but it used to be breed by Chinese since 1000 years. Selecting them, in China and Japan, there were obtained a lot of varieties as both shape and coloration. In England it was introduced in 1691, and then it spread to Portugal and after that in the entire Europe.

Because there are plenty of goldfish varieties we`ll describe the most common one. It looks similar to carps but it is less oblate on flanks and has larger scalds. The main form, `gibelio` is spread in Eurasia. They are breed in large and well aerated and filtrated aquariums. We won`t plant many aquatic plants in the aquarium. For veiled forms we`ll set up higher aquariums in order to mark the beauty of the tail. The temperature has to be between 15 and 18° C because at higher temperatures the protective mucus layer will dissolve and the aquarium water will have a foggy aspect. After that the decrease of the temperature will harm the fish because the mucus layer has a protective use against low temperatures. Only for selected varieties the temperature may be around 20-22° C.

Let`s talk about the reproduction of goldfish. First we have to be sure we have at least one mature couple. The perfect way uses a female and three males. Goldfish are mature after a year, but for that we have to breed them in a minimum 200 liters aquarium (for 4 fish). We also have to provide much and varied food, a good filtration and a temperature around 18-20° C. For reproduction we have 2 models which we can follow: free spawn and `milking` the couple.

This specie doesn`t exist in nature; it looks like it is a mutation of Brachydanio rerio specie. One of the facts that confirm this supposition are the fertile hybrids obtained by spawning Brachydanio rerio with Brachydanio frankei. It is also called leopard fish. As body shape, they are similar to the specie from which they are native, males have a more slender and the females have the abdominal area more voluminous.

The background of the body is golden, and it has lithe round spots colored in dark colors. The fins are color less. The anal and caudal fins are also marked with spots. The female has a lighter coloration. The spawning is similar to the Brachydanio albolineatus specie.

The specie is spread in the eastern India. In aquaria it is known as zebra fish. They have a slender body, medium oblate flanks; the mouth is in the superior part of the body, showing us that it is a fish for the surface of the water, or for the medium level. It has 2 pairs of mustaches. The female is larger than the male, reaching 4.5 cm length. The male is more slender and the female has a larger abdominal area.

For males, the background is golden and for females it is white-yellow. On lateral sides it has 4 transversal lines colored in blue. The lines cover the entire body and tail, even the anal fin. The abdomen is white and the dorsal fin is olive-yellow with blue hem. The unpaired fins are color less.

It`s easy to reproduce, following the same steps as for Brachydanio albolineatus.

The specie is spread in eastern India, Sumatra, where it lives in running waters. It`s a slender fish, with a prolonged body, medium flank oblate. In the superior part of the mouth it has 2 pairs of mustaches, the inferior one being longer. The anal fin is prolonged starting from the same place as the dorsal. It can reach 5 cm length. The body color is blue to violet; the back is dark blue-grey with some shining scalds. The abdomen is light blue-silvery. It has a longitudinal line dark red to orange, with a blue-green hem. The anal fin is red-orange near the body and green-red on the opposite part. The female is less colored than the male.

They live in bench, being an active fish, that`s why they need large aquariums with a planted back area and space for swimming in the front part. The optimal temperature is 22-24° C, but in winter time it can also be 18-20° C. It eats almost anything from living food to dry food as flakes. For reproduction they need 10-15 liters aquariums. The position of the aquarium has to be as in the morning a ray of sun fall into the aquarium water. The chemistry of water is not important, but the water must be fresh. In the reproduction aquarium we`ll have to mount a nylon netting in order to protect the eggs. We`ll also have to plant some aquatic plants as: Nittela or Myriophyllum. The aquarium water must be filtrated and aerated for 3 days before adding the fish. In the evening we`ll add 4 females and 6 males which can spawn up to 600 eggs. The fry will hatch after 24-30 hours. In the first 3-4 days the fry are stick on the aquarium sides. After they start to swim free we`ll feed them with infusors or yolk of egg. If we use egg, this has to be given in small quantities not to alter the water. In aquarium you`ll also add a small filter with few bubbles because the fry is sensitive at water motion. The sexual difference is obvious: while males are slender and thin, the females are more voluminous (especially in the reproduction period).

Trichogaster has a more prolonged than high body. It has a small mouth in the superior part of the body. The male has more marked lips. It can reach 15 cm in aquariums, but in nature it is much bigger. Trichogasters have 2 varieties of body coloration:
- carroty-violet
- shining blue
The male has a longer and sharper dorsal fin, while the female`s is short and round. Another difference of the female is that after she becomes mature, her abdominal area is very turgid. The blue shining variety received the name: Trichogaster trichopterus sumatranus. They are spread all over India.

For reproduction Trichogaster trichopterus needs a temperature of 25-27° C, and for normal care they only need 22-24° C. The chemistry of water doesn`t have much importance. The reproduction aquarium must be about 30-40 liters and the water level can be 20-25 cm. On the surface of the aquarium water you`ll add some floating plants like: Riccia fluitans or Ceratopteris species. These plants serve as a hiding place for the female and they are also a good support for the bubble nest, which is constructed by the male using a mouth secretion. The female should be introduced in the evening, and the male next morning. After a few minutes of accommodations the male will alternate the female chase with the bubble nest construction. The bubble nest made by the male can sometimes be very big, about half of the aquarium, or it can be small, it can even be absent. The eggs are very oleos so they don`t fall down from the bubble nest; they are under the strict supervision of the male. Immediately after they spawn, the female must be taken out of the reproduction aquarium because the male will hurt her in order to send her away from the nest. In order to take out the female, from an aquarium where hundreds or even thousands of fry swim, you`ll need nylon netting. You need a netting like that not to catch the eggs (when you remove the female) or the fry (when you remove the male). The fry hatches after about 24-30 hours and for the next 3-4 days it remains in the nest. After the offspring swims free, you`ll remove the male and start feeding the baby fish. We can administrate them infusors or yolk of an egg. If we feed them with yolk, this has to be administrated 3-4- times a day and in small quantities. At this point we`ll add a filter with few bubbles because the fry is very sensitive to water movement. In the first days, there are a lot of fish and we`ll have to feed them well, the quantity of food should be correlated with the number of fish. If we don`t feed them well, tome of them will grow and eat the little ones, the number of fish can increase dramatically after a week or two. If we feed them well, they`ll grow nicely and after 3-4 days we can administrate Artemia (baby brine shrimp). For 1-2 days we`ll keep feeding them with infusors or yolk of egg in order to help the fry which remain small.

The aquarium must be covered with a glass plaque, especially between the 3rd and 5th weeks when they develop their labyrinth, any difference between the air temperature and aquarium water temperature will induce their death. If we feed the fry with Artemia or micro worms, we`ll have less trouble because these `animals` don`t multiply much and they don`t dirty the water as the yolk does. Starting with the 5th feeding day, we`ll add fresh water, at the same temperature, in order to full the aquarium. After 3-4 weeks the fry will start looking like their parents. If they developed differently, we`ll have to permanently select them. The reproduction way is similar to the species of Colisa and Trichogaster leeri.