Tropical Aquarium Fish

The silver dollar (Metynnis argenteus) is a tropical fish belonging to the Characidae family which is closely related to pirahna and pacú. Originating in the Tapajós River basin in South America, this somewhat round-shaped silver fish with slight red-tinged anal fin is mostly found in tanks kept by fish-keeping hobbyists. It will grow to a maximum length of 5.5 inches (14 centimeters).

The silver dollar is a peaceful schooling species that spends most of its time in the mid- to upper-level of the water. Its maximum lifespan is more than 10 years. An egg-layer, the adult fish will spawn around 2,000 eggs. This breeding occurs in soft, warm water in low light.

Silver dollars natively live in a tropical climate in the sides of weedy rivers. They prefer water with a pH of 5–7, a water hardness of up to 15 dGH, and an ideal temperature range of 75–82 °F (24–28 °C). Their diet is almost exclusively vegetarian and in captivity they will often eat all the plants in a tank. They will also eat worms and small insects.

The Common Hatchetfish or River Hatchetfish (Gasteropelecus sternicla) is a tropical fish belonging to the Freshwater Hatchetfish family (Gasteropelecidae). Originating in the South America in the Peruvian and middle Amazon, the Guianas and Venezuela, it grows to about 2.5 inches (6.5 cm). The fish gets its name from its relatively large protruding belly which resembles a hatchet.

The River Hatchetfish is a schooling species best kept in groups of five or more that spends most of its time in the top-level of the water where it searches for food. The fish can be peaceful or aggressive. Its typical lifespan in captivity is around five years.

These Hatchetfish natively live in streams in a tropical climate and prefer water with a 6.0 - 7.0 pH, a water hardness of up to 15.0 dGH, and an ideal temperature range of 73 - 81 °F (23 - 27 °C). A carnivore, their diet consists of annelid worms, insects, and crustaceans. The fish will often jump out of the water to catch small aerial insects. Because of this behavior, they may jump out of aquarium tanks.

The Mexican tetra (Astyanax mexicanus) is a freshwater fish of the characin family (family Characidae) of order Characiformes.[1] [2] The type species of its genus, it is native to the Nearctic ecozone, originating in the lower Rio Grande and the Neueces and Pecos Rivers in Texas as well as the central and eastern parts of Mexico.

Growing to a maximum overall length of 12 cm (4.7 in), the Mexican tetra is of typical characin shape, with unremarkable, drab coloration. Its blind cave form, however, is notable for having no eyes and being albino, that is, completely devoid of pigmentation; it has a pinkish-white color to its body.

This fish is reasonably popular among aquarists. This is especially true of the blind cave form.

A. mexicanus is a peaceful species that spends most of its time in the mid-level of the water above the rocky and sandy bottoms of pools and backwaters of creeks and rivers of its native environment. Coming from a subtropical climate, it prefers water with 6.0–7.8 pH, a hardness of up to 30 dGH, and a temperature range of 20 to 25 °C (68 to 77 °F). In the winter it migrates to warmer waters. Its natural diet consists of crustaceans, insects, and annelids, although in captivity it is omnivorous.

The Mexican tetra has been treated as a subspecies of A. fasciatus, the banded tetra, but this is not widely accepted.

Species name: Hyphessobrycon Flammeus

Synonym: Hyphessobrycon flammeus

Common name: Flame Tetra / Von Rio Tetra

Family: Characidae

Order: Cypriniformes

Class: Actinopterygii

Maximum size: 5 cm / 2 inches

Environment: freshwater

Origin: South America

Temperament: Peaceful

Company: Hyphessobrycon Flammeus (Flame Tetra) is suitable for community aquariums.

Water parameters: Temperature 24-27°C / 75-79°F; pH 6.0 – 8.0

Aquarium setup: Hyphessobrycon Flammeus (Flame Tetra) prefers a well planted aquariums with lots of hiding places and some free areas to swim on. They also prefer dimmed lighting. Hyphessobrycon Flammeus (Flame Tetra) are very undemanding and can be kept in most water conditions as long as extremes are avoided. They should always be kept in groups of 10 fishes or more.

Feeding: Hyphessobrycon Flammeus (Flame Tetra) accepts flake food..

Breeding: Hyphessobrycon Flammeus (Flame Tetra) is easily breed and produce up to 250 eggs. The eggs will hatch in 24-50 hours. The parents eat their own eggs and they should therefore be removed from the breeding aquarium as soon as the eggs has been laid. The eggs wil not hatch if exposed to light.

The Colombian Tetra comes from Colombia. It is also know as the “Columbian” Tetra, the Blue-Red Columbian and the Red Tail Mirror Blue Tetra. It was known by the scientific name Hyphessobrycon ecuadoriensis and more recently as Hyphessobrycon columbianus, which more accurately describes its Colombian origin. It has only been available in pet stores since 1995 and has become a very popular tetra. The Colombian tetra has a band of blue across the upper body with red in the fins, especially in the caudal fin. The lower body is silvery.

The Colombian is very hardy and is a good beginner fish, however it is fairly aggressive and should only be kept with more nippy, active and aggressive tetras, such as the Serpae, Blind Cave, Buenos Aires and the Silver Tip Tetra. They are definitely not good companions for smaller tetras and guppies. Colombians will be happier and show better colors when kept in groups of 6. They appreciate a well planted tank, but the will eat plants. Colombians will eat flake foods, freeze dried bloodworms and brine shrimp.

Males and females are difficult to distinguish by coloring. The female is larger and broader, especially when laden with eggs. Soft, slightly acidic water is best for breeding and lighting should be greatly dimmed. Pairs should be separated for more than a week before breeding and fed a variety of foods. Tetras have adhesive eggs, so fine leaved plants or spawning mops should be used to catch the eggs. Colombians will spawn multiple times over a period of days. The parents should be removed after spawning. The fry are very small. Fry should be fed infusoria and the finely ground flake foods.

In aquaria Paracheirodon innesi is known as neon fish. Till not long ago its name was Hypehessobrycon innesi. The specie is spread in the west of Brazil, Columbia, north of Peru, in superior area of Amazon to Iquitas, in Amazon`s affluent: Putamayo and Purus. It lives in the dark water of these rivers and Dr. H. Axelrod has emitted a hypothesis assuming that the shining lateral line helps them find each other in the reproduction period. They have a slender body, with medium oblate flanks, a dull mouth; the abdomen is more slender to males than females, especially when they are in the reproduction period. Paracheirodon innesi can reach 4 cm. They have a lateral shining blue or green line, depending on the light flow angle, which goes from the superior part of the iris to the adipose fin area. Under this shining line, there is a dark red line which can go to the tail. The iris has shining golden points, the back is light olive, slivery abdomen, uncolored fins, and the first rays of the anal fin are white.

Paracheirodon innesi obtained a fame of a hard to breed fish. These things are said by people who don`t know much about aquaria, not by experienced fish breeders. In common aquariums, they don`t request anything different than other fish do. On the contrary, they are less sensitive than other species of aquarium fish. Aquarium fish breeders who say it`s a sensitive fish confound the breeding conditions with the reproduction ones. Indeed, for breeding Paracheirodon innesi needs some extra special conditions, but which we found for other species too. So we first need a good couple for spawning. It was found out that the fish kept in aquarium water with more than 8°dGH are not 100% appropriate for reproduction. So the first condition is to have aquarium water with 4-7°dGH. Even if they spawn, there are big chances to have few eggs, and the fry is susceptible of getting the neon disease.

The feeding is also very important. In order to have a good reproduction couple, we have to feed them with living food, but maximum 2 times a week with fresh and clean tubifex. The food has to be diversified. In aquariums they also eat dry food as flakes. Another important factor is the temperature. You mustn`t keep them at more than 19-20° C and for reproduction only 20° C.

Characins family is part of Characoidea subclass, which is included in Cypriniformes class. Characidae fish come from freshwater fish from Africa, South and Central America and south SUA. The most specific thing of this family fish is their adipose fin which makes them look like the salmonides. They are related to carps too, but the difference between them is represented by the presence of this adipose fin, the lack of mustaches and the denture. Most Characidae fish have small teeth, different by shape and composing material. Some of them have very sharp teeth for the use of rending the food.
Characidae family contains about 1300-1400 species of fish. All the species prefer clean and soft water, with a light acid pH. The temperature of the aquarium water should be between 22 and 26° C. They like well planted aquariums, with zones where you can have morning light coming from Sun. For reproduction they need aquatic plants with small leaves: Fontinalis or Myriophyllum. The water for spawning has to be soft and light acid, with a temperature of 25-27° C. You have to chose an active pair, which shows signs of reproduction `plans`, from the common aquarium. In the reproduction aquarium, the fish can be fed only with Enchitreis which stimulate the spawning. All Characidae species eat their spawn, that`s why you must take them out of the reproduction tank. The fry hatches after 24 hours and they swim free after 3-5 days.
Gery says that Characoidea subclass divides into two families:
- Characoidae, which have a long anal fin
- Erytrinidoidea, with a short anal fin.
In Characoidae family we include these subfamilies:
- Characidae with genus: Hemigrammus, Hyphessobrycon, Megalamphodus, Moenkausia, Tayeria, Alestens, Micralestes
- Serrasalmidae with genus: Metynnis, Milossoma, Serrasalmus
- Gasteropelecidae with genus: Thoracharax, Carnegiella, Gasteropelecus.