Most aquarists will only know a few tetra species from Africa. Here, Michel Keijman showcases a wide selection found across the waters of Cameroon.
MICHEL KEIJMAN Michel is author of many fish books, including the acclaimed Freshwater Fishes of Cameroon.
ALESTIDAE, THE FAMILY of freshwater fish commonly known as African tetras, constitutes by far the greatest diversity of African characiforms, with current estimates of 118 species distributed among 19 genera. They are found in various parts of Africa, including the Congo River basin, the Nile River, and other rivers and lakes throughout the continent. Some are pelagic or semi-pelagic. And they are easily distinguished from the similarly-shaped cyprinids by sharp teeth on the jaws and a small adipose fin.
Some of the most familiar include the African tigerfish, Hydrocynus vittatus, the Congo tetra, Phenacogrammus interruptus, and the Nurse tetra, Brachyalestes nurse. In the wild, these tetras can be important food fish for African communities, and prey for larger fish and other animals.
Habitats and feeding
As young Alestidae mature, they go through different stages of development, which correspond to their feeding needs, biological needs, and their ecological and physiological needs. That means they may occupy different biotopes at different life stages.
In general, it can be said that small species need different food to, and therefore live in different parts of a river from (and therefore in a completely different habitat), larger species that eat larger food. Fish eating relatively large fish as prey will typically occur in a different environment to those that feed on tiny benthic organisms.
It is therefore not surprising that in a river where there are many different habitats present (free open water zones, areas where there is a lot of current, riparian areas where there is a lot of shelter by means of branches and grasses hanging in the water), there are as many different fish filling the niches. But also consider, for example, what the bottom of a river consists of. A modern soil, a soil that consists of pebbles and gravel, or one that has a sandy bottom—all of these influences mean that each habitat with its particular conditions leads to the presence of one or more specific species.
As I’ve alluded to, there are many different species within the family with different food needs. There are herbivorous, omnivorous and piscivorous species. But while there
