Aquarium Fish Species Profile-Part 5

Colombian Tetra / Red-Blue Columbian Tetra

Scientific Name: Hyphessobrycon columbianus
Size: 2 ½” to 3”
Temperature: 70 – 76 degrees Fahrenheit
Alkalinity: Moderate
Origin: Acandi River Basin, Colombia

The Colombian Tetra (also known as the Red-Blue Colombian Tetra – but since it is the only fish called “Colombian Tetra” I see no reason to add “Red-Blue” to its name) is a large, peaceful tetra that comes from the Acandi River Basin in Colombian, in South America. Even though it has not been in the hobby as long as many other fishes, the Colombian Tetra is very popular and is farmed in Florida and throughout the Far East. Wild-caught Colombian Tetras are really not seen in the hobby anymore, and all of these fish come from aquaculture sources.

Even though the Colombian Tetra is large for a tetra, it has a fairly docile demeanor, and will usually not do any damage to other fish that are roughly its size. The fish itself is silver, with a blush of red on all of the fins, and a blue coloration from the lateral line up. Males are usually larger, and in a school of Colombian Tetras, the dominant male will always show the most color. Colombian Tetras must be kept in as large a school as possible – and single fish can become rogues and do damage to their tankmates. They are a very easy fish to get to spawn, but raising the babies to good size takes a little longer than with other similar fish.

In the aquarium, the Colombian Tetra will adapt to any pH range around neutral (7.0), and it will do well in all but the hardest water. Since these fish have been commercially farmed for quite a while now, they are almost always available. They will do fine in a community tank of fishes of their same size, and are not in the least bit finicky about food, eating anything and everything that is offered them.-David Lass.

Congo Tetra

Scientific Name: Phenacogrammus interruptus
Family: Alestidae
Size: 4 inches
Temperature: 74 – 82 degrees Fahrenheit
Alkalinity: soft to moderate
Origin: Congo River Basin in Africa

The Congo Tetra is one of the few “tetras” that comes from Africa, and is definitely the best known and most frequently kept in aquariums; most tetras come from South America. The Congo Tetra is a strikingly beautiful fish, large and full-bodied with flowing fins. The basic background coloring of the fish is silver, with the bottom half suffused with an aquamarine blue, and the upper portion a gold. These colors deepen as the fish gets older and larger, and in dominant males, the colors are very deep, and the fin edges extended; the tail in males gets long and feathery, and with mature fish, it is very easy to tell males from females and to see which male is dominant. Congo Tetras do best in groups of six or more fish, and they are very active, making an excellent display for a large and long aquarium. They like to be able to swim in and out of plant thickets, and they prefer having shaded places (from floating plants) where they can stay.

Congo Tetras are an ideal fish for a community tank of similar size, and equally pleasant, fishes. They will get along fine with any other peaceful fish of their same size, but they do not do at all well with any fish that is in any way aggressive. They do well in water that is neutral to acid pH, with moderate hardness. A species tank of Congo Tetras, and some catfish or other bottom dwellers, make an excellent display. They will thrive on the regular prepared dry foods that other fishes eat, and they also appreciate some frozen (or live) foods a couple of times a week.

While the Congo Tetra is a typical egg-scatterer, they are not often bred by hobbyists. They are commercially farmed throughout the Far East, and fish with minor variations, such as more blue, or a stronger yellow, are often offered for sale.

Convict Cichlid

Scientific Name: Archocentrus nigrofasciatus, formerly Archocentrus nigrofasciatum
Family: Cichlidae
Size: 3 to 4 inches
Temperature: 74 to 82 degrees Fahrenheit
Alkalinity: around neutral, moderate hardness
pH: 6.6 to 7.2
Origin: Central America

The convict cichlid is often the first fish a budding aquarist breeds — they are almost impossible to keep from reproducing. Often the first signs that a convict cichlid family is underway will be the convicts taking over at least half of the tank, depending on how big it is and the other fish all cowering in the corners at the opposite end.

The convict cichlid is not a community tank fish under normal circumstances. When breeding this fish becomes an absolute terror, having no compunction about taking on fish twice its size or the hand of the aquarist if it comes too close. Males get long extensions to the dorsal and anal fins, and are generally larger. Females, when they are ready to breed, get a reddish glow to their stomachs.

The convict is available in a number of color varieties. Blackish-brown striped is the normal wild type. There is also something called the “pink convict,” which is a xanthic form and just as hardy and nasty as the normal color. Because the convict is so easy to breed, all of the fish seen in stores are commercially (or hobbyist) raised and there are many variations on the theme.

The convict is not a fussy eater, and will consume anything offered, and also that which is not, such as the fins of other fish. The convict should be provided with a significant amount of vegetable matter in its diet, which it will also obtain by chewing up any plants in the tank.

Every aquarist should keep the convict cichlid at least once. It is the easiest introduction to the world of cichlid behavior and parenting.

Cory Fish


Cories are South American catfish of the family Corydoradinae. They are temperate and tropical armoured catfish. Cories are the most popular catfish for aquaria, and most species remain relatively small. It is recommended that they be kept in small schools rather than individually.