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 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. They also have different colors and extensions in the caudal fin.
Aquarium trade and keeping
Congo tetra are a popular aquarium species. However, their large size and active behavior makes them unsuited for most smaller tanks. They easily adapt to captive diets like pellets and frozen foods, though they will still hunt down live foods when offered. They have successfully been bred in captivity and captive bred individuals are commonly available. Whilst they can be kept healthy on a slightly wider range of water parameters, breeding often requires water parameters more similar to their natural habitat. Bad water quality has been known to affect male fin development and lead to loss of coloration.
- 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: 
- Snoeks, J.; Laleye, P.; Moelants, T.; Contreras-MacBeath, T. (2010). "Phenacogrammus interruptus". IUCN Red List of Threatened Species. 2010: e.T167968A6428241. doi:10.2305/IUCN.UK.2010-3.RLTS.T167968A6428241.en.
- Media related to Congo tetra at Wikimedia Commons
- Fishbase: http://www.fishbase.org/summary/speciessummary.php?id=10660
- Congo Tetra Fact Sheet: https://web.archive.org/web/20110120185412/http://bettatrading.com.au/Congo-Tetra-Fact-Sheet.php