The Congo tetra is not as commonly known as the Neon tetra and the Cardinal tetra, but among more experienced fish keepers it is treasured for its beauty and interesting behavior. The scientific name for the Congo tetra is Micralestes interruptus. Just like its common name implies, it is native to Congo. You can only find Congo tetra in the Zaire River basin in Central Africa.
Congo tetras have a shimmering colouration that can vary considerably between different specimens. The body is usually of an olive green shade, while the belly is of a violet or strong purple colour. The sides feature a characteristic light brown stripe, under which a myriad of smaller green or golden stripes are found. The fins are grey or sporting a tint of pale red, and the tail fin and anal fin have white edging. On the anal fin, you can se a dark dot.
The body shape of the Congo tetra is elongated, just like the other tetras, and the body of a male Congo tetra grow up to 3.5 inches long. Females stay smaller, typically under 2.5 inches. You can also sex this species by looking at the caudal fin; if it is very long you are looking at a male Congo tetra. The male is also equipped with a large dorsal fin that goes all the way back to the caudal fin. Both sexes have large eyes and scales.
Since the Congo tetra is a schooling fish species, you should always get at least more than 5 fish in your aquarium. If kept alone, it will get stressed and more prone to illness. Avoid keeping Congo tetra with aggressive fish species, or species that will consider it food. This fish works well in a community tank with other fish species that appreciate the same environment.
The aquarium should ideally include a lot of plants, since a barren aquarium make Congo tetras feel insecure. Keep the temperature between 73º and 79º F (23º and 26° C). The Congo tetra will do best in soft and acidic water, but it can usually adapt to harder conditions in captivity and a pH-value up to 7.5. Keeping the pH around 6 is however much better. Powerful circulation is recommended and the levels of soluble waste must be kept low.
Wild Congo tetras are insectovores, but they can be trained to accept flakes and other types of ready-made fish food in captivity. Keeping your fish on flakes only can make their coloration dull, so if you want your tetras to stay beautiful you should ideally give them occasional treats in the form of mosquito larvae, daphnia, brine shrimp or similar.
When you find Congo tetras in pet shops, they are usually wild caught. Congo tetra is not very difficult to breed in aquariums, but captive bred specimens tend to be of lower quality compared to wild caught ones. Captive breed specimens often have shorter finnage and less striking colours. Hopefully, responsible breeders will soon start producing high-quality captive bred Congo tetras for the aquarium trade to ease the burden on the wild populations. Responsible harvesting of wild populations can also provide a sustainable source of income for those living around the Zaire River basin.