Congo Tetra - Phenacogramus Interuptus

Congo Tetra | Africa's Most Stunning Schooling Fish

The Congo Tetra (Phenacogrammus interruptus) is widely regarded as the most spectacular tetra in the freshwater aquarium hobby — and it's easy to see why. Native to the slow-moving streams, marshes, and tributaries of the Congo River Basin in Central Africa, this large, iridescent tetra shimmers with shifting waves of blue, gold, orange, violet, and green as it moves through the water. Adult males develop dramatic flowing fin extensions that trail behind them like ribbons, giving them a presence and elegance that few other schooling fish can match.

Despite their showstopping appearance, Congo Tetras remain surprisingly underappreciated in the hobby — often passed over in fish stores because juveniles look nothing like the breathtaking adults they will become. If you're patient enough to grow them out, the reward is one of the most genuinely impressive displays a freshwater aquarium can offer.

The Only African Tetra in the Hobby

While the vast majority of popular tetra species come from South America, the Congo Tetra is the only commonly kept African tetra in the aquarium trade — making it a genuinely unique addition to any freshwater setup and a natural choice for African biotope aquariums alongside species like Butterfly Fish and African Dwarf Frogs.

Congo Tetra Care Guide

Care at a Glance

• Scientific name: Phenacogrammus interruptus
• Also known as: African Tetra
• Adult size: Males up to 3.5 inches (9 cm), females up to 2.5 inches (6 cm)
• Minimum tank size: 30 gallons — longer tanks preferred over taller ones
• Temperature: 73–82°F (23–28°C)
• pH: 6.0–7.5
• Hardness: 3–18 dGH — soft, slightly acidic water preferred
• Best kept in groups of 8 or more
• Lifespan: 3–5 years with good care

Congo Tetra Tank Setup

A well-planted aquarium with open swimming space, subdued lighting, and gentle water flow reflects the Congo Tetra's natural blackwater habitat perfectly. Floating plants to diffuse light, driftwood, and dark substrate will help bring out the full depth of their iridescent colouration and make them feel secure. Tannins from Indian almond leaves or driftwood are beneficial and replicate their natural environment beautifully. A tight-fitting lid is recommended — these are active swimmers and can jump.

Feeding Your Congo Tetras

Omnivores that do best on a varied diet. A high quality flake or micro pellet makes a solid staple, supplemented regularly with frozen or live foods such as brine shrimp, daphnia, bloodworm, and small insects. Variety is key to maintaining their vibrant colouration and long term health.

How Many Congo Tetras Should You Keep?

Congo Tetras are a schooling species and should be kept in groups of at least 6, though 8–12 produces the best schooling behaviour and the most impressive colour display. A mixed sex group with roughly two females per male helps reduce competition between males. In a proper school, males will display their finest colours as they compete for female attention — creating a constantly shifting, shimmering spectacle that is one of the highlights of the freshwater hobby.

Congo Tetra Tank Mates

• Other large, peaceful tetras and rainbowfish
• Dwarf cichlids such as Apistogramma and Rams
• Corydoras and peaceful bottom dwellers
• Peaceful barbs and larger rasboras
• Gouramis and similarly sized community fish
• Avoid small fish that may be nipped — Congo Tetras have larger mouths than most tetras and may bother very small tank mates
• Avoid fin-nipping species such as Tiger Barbs, which will target the males' flowing fins