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Passport
- Family
- Tetras
- Grows to
- 6 cm (2.4")
- Lives
- 3–5 years
- Temperament
- Peaceful
- Care
- Intermediate
- Swims
- Mid-water
- Keep
- In a group of 6 or more
- Water
- 23–28 °C (73–82 °F)
Democratic Republic of the Congo
Care requirements
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On record for Congo Tetra: adult size, lifespan, minimum tank, temperature, ph, hardness, minimum group, diet, care level, swim level, tank length.
A figure that is not on record is left out rather than guessed. One marked Suggested comes from keeping knowledge rather than a page.
- Minimum tank 114 L / 30.0 US gal
- pH 6–7.5
- Hardness 3–18 dGH
- Diet omnivore
- Tank length 120 cm minimum
Care notes written from general aquarium knowledge, not from the cited sources.
About
Congos are the tetra that grew up. An adult male is a broad, iridescent fish that shifts blue, gold and violet as he turns, with a long feathered tail and dorsal that trail behind him — nothing else in the tetra section of a shop looks remotely like it.
They're African, from the Congo basin, which puts them in a different world from the South American tetras they sit beside in the shop. Most stock is farm-bred in the Far East and Eastern Europe now.
The catch is that they're shy for their size. A big fish that spooks easily needs a calm tank and confident company, and people who buy them for a boisterous community are usually disappointed by how little they see of them.
Tank setup
Give your congos length above everything else. They're active, they cruise, and they need a run to do it in — this is not a fish for a tall showpiece cube.
Plant it well and leave the middle open. An African arrangement with driftwood branches, anubias on the wood and floating plants overhead is exactly right and happens to be easy to maintain.
Dim the light or shade it. Floating plants do the job, and congos are much more willing to come forward under a broken surface than a bright one.
Keep the water soft and slightly acidic with good circulation. They came from a big river system and they like water that moves.
Feeding
Congos are unfussy omnivores and will eat whatever's going, which is a relief in a fish this size.
Their colour depends on what you feed them, though, more visibly than in most tetras. Live and frozen food should be a real part of the diet rather than an occasional treat if you want the iridescence and the fin growth people buy them for.
They're big enough to take proper-sized food. Larger flake, sinking granules, whole bloodworm and chopped prawn are all within reach.
Avoid: a flake-only diet, which produces a drab, short-finned fish that looks nothing like the one on the shop poster.
Filtration and flow
Give them good circulation and plenty of turnover. Congos are strong swimmers from flowing water and they use a current rather than hiding from it.
Filter properly for the bioload. They're substantially bigger than the tetras they get grouped with and they eat like it.
Keep the water soft if you can. Hard alkaline water won't kill them but it takes the edge off the colour, and the difference is easy to see side by side.
With plants
Congos are safe with most plants, though they'll graze soft new growth if the tank is underfed. Anubias, java fern and other tough-leaved plants are the reliable choices.
Floating plants matter more than anything rooted. The shade is what settles them, and a congo tetra in a brightly lit bare tank spends its life at the back.
Nothing gets dug up — they have no interest in the substrate.
Health
They're hardy once settled and there's no ailment specific to them. Nearly every problem people report is stress rather than disease.
The fins are the vulnerability. Never keep congos with fin-nippers — barbs, serpaes, anything with that reputation — because those trailing male fins are exactly the target such fish look for, and the damage takes months to grow back if it grows back at all.
Watch for a group that won't leave the back of the tank. That means the light is too bright, the tank mates are too pushy, or the group is too small.
Breeding
Congos will spawn in a well-kept tank, and they need soft acidic water to do it — this is one of the species where hard water simply stops the eggs developing.
They scatter eggs in the morning, often triggered by the first light hitting the tank, and they eat them enthusiastically afterwards. A separate tank with a mesh floor or a thick mat of moss is the practical approach.
The eggs take longer to hatch than most tetras, and the fry are large enough to take baby brine shrimp almost immediately, which makes rearing them easier than the fiddly small tetras. Keep the tank dim while the eggs develop.
Tank mates
Avoid10
- Convict Cichlid Convict Cichlid grows to 15 cm against Congo Tetra at 6 cm, big enough to eat it.
- Jewel Cichlid Jewel Cichlid grows to 15 cm against Congo Tetra at 6 cm, big enough to eat it.
- Least Killifish Congo Tetra grows to 6 cm against Least Killifish at 2 cm, big enough to eat it.
- Scarlet Badis Congo Tetra grows to 6 cm against Scarlet Badis at 2 cm, big enough to eat it.
- Common Goldfish Common Goldfish is not safe with Congo Tetra: common goldfish and tetras are a bad pairing.
Only with care11
- Chinese Algae Eater Chinese Algae Eater is aggressive and Congo Tetra is peaceful.
- Cherry Barb Congo Tetra and Cherry Barb are an uneasy mix: barbs and tetras are a pairing to watch.
- Gold Barb Congo Tetra and Gold Barb are an uneasy mix: barbs and tetras are a pairing to watch.
- Odessa Barb Congo Tetra and Odessa Barb are an uneasy mix: barbs and tetras are a pairing to watch.
- Paradise Fish Paradise Fish is a risk to Congo Tetra: large gouramis and tetras are a pairing to watch.
No conflict is recorded with the other 85 species in the database, so nothing to flag. 2 species are not covered at all, so they could not be judged either way.