Congo tetra

Overview

The Congo tetra (Phenacogrammus interruptus) is the showpiece of the tetra world — a large, deep-bodied African species shot through with rainbow iridescence, the mature males trailing long, feathery grey-white fins. At up to 8.5 cm it’s far bigger than a neon, and it needs a correspondingly larger, longer tank. Given that space and a proper shoal, it’s a peaceful, hardy and genuinely spectacular centrepiece fish.

Tank & water

A big, active tetra that needs length and numbers:

• A cycled tank of at least 110 litres — cycle the aquarium first, and see how many fish in an aquarium for a fish this size.
• Temperature 23–27 °C with a reliable heater.
• Soft to slightly hard water (pH 6.0–7.5). Strong filtration with moderate flow keeps a bigger bioload clean.
• A planted layout with open swimming lanes — plants and a dark substrate around clear central space for the shoal to cruise.

Feeding

Congos are hearty omnivores. A staple of quality flake or larger pellet, plus frozen or live daphnia, brine shrimp, bloodworm and some vegetable matter, keeps their iridescence strong and fins in good shape. Feed once or twice a day. Browse the fish food hub and best fish food picks.

Tankmates

Peaceful despite their size, Congos suit larger community tanks with calm, similarly sized fish — other tetras like lemon tetras, rainbowfish, peaceful barbs, larger rasboras, corydoras and gouramis. Their own fins can be nipped, so avoid known fin-nippers, and don’t house them with fish small enough to be intimidated. A shoal of Congos as the tank’s feature works beautifully.

For a larger planted community, our best aquarium for beginners guide covers the basics of getting a bigger tank stable — Congo tetras reward the extra space with real spectacle.