The Congo tetra has a typical full-bodied tetra shape with rather large scales. When mature, the iridescent colors of the Congo tetra run through the fish from front to back, starting with blue on top changing to red through the middle, to yellow-gold, and back to blue just above the belly. It is not its fluorescent colors that make this tetra so distinct, but rather its tail fin, which develops into a most beautiful grayish-violet feathery appendage with white edges. The males get up to 3.0 inches (8.5 cm). Females up to 2.75 inches (6 cm). The male is larger with more color, also the tail fin and dorsal fin are more extended.
Aquarium keeping 
|This section contains instructions, advice, or how-to content. (May 2013)|
In the aquarium, mimic the natural habitat. The Congo tetra requires soft, peat-filtered water and a darker substrate. They are most comfortable in an aquarium with lower light levels. The beautiful rainbow colors of this fish will also show best in lower light levels. These fish are easily frightened by aggressive tank mates and loud noises and may wait for you to leave the aquarium before they will feed. It is a peaceful schooling fish and needs a large aquarium to thrive and develop its full beauty. Any aquarium of less than 30 gallons will not be suitable for a proper school of these fish. Hardness: 4-18 ° dGH Ph: 6.2 Temperature: (75-81 °F) 24-27 °C
Since they are omnivorous the Congo tetra will generally eat all kinds of live, fresh, and flake foods. To keep a good balance give them a high quality flake food every day. Feed brine shrimp (either live or frozen) or bloodworms as a treat.
Social behavior 
They are generally a good community fish but they may try to bite smaller fish. Also, they may eat smaller plants. They sometimes like to nibble on softer plants and young shoots.
Breeding and reproduction 
Congo tetras are egg layers. Some keys to breeding them are a large aquarium, peat-filtered water, and bright lighting to initiate spawning. They will lay up to 300 eggs that will drop to the bottom. The fry are large enough to eat freshly-hatched brine shrimp.
Conservation status 
See also 
- Ultrastructural Examination of Spermiogenesis and Spermatozoon Ultrastructure in Congo tetra Phenacogrammus interruptus Boulenger, 1899 (Ostariophysi: Characiformes: Alestidae)
Author: Pecio, Anna Folia Biologica, Volume 57, Numbers 1-2, December 2008, pp. 13–21(9) Publisher: Institute of Systematics and Evolution of Animals, Polish Academy of Sciences
- IUCN Red list: http://www.iucnredlist.org/apps/redlist/search