What tank size does a Congo Tetra need?

A Congo Tetra needs an aquarium of at least 110 litres (29.1 US gallons) with a footprint at least 120 cm (47.2 in) long — for this species, swimming length matters as much as raw volume.

What water parameters does a Congo Tetra need?

Congo Tetra does best at 23–28 °C (73.4–82.4 °F), pH 6–7.5 and a general hardness of 3–18 °dGH.

What group size does a Congo Tetra need?

Congo Tetra is a social species — keep a group of at least 6 so natural behaviour emerges and stress stays low.

Is the Congo Tetra suitable for beginners?

Congo Tetra sits in the middle of the difficulty scale — manageable for a careful beginner who has done the reading, but it has specific needs worth researching first.

Species library

Congo Tetra

Phenacogrammus interruptus

Alestidae

FishDifficulty: ●●●○○Data: well-established

📷 7TP (Krzysztof Bartosik) · CC BY-SA 4.0 · resized · Wikimedia Commons

Congo Tetra — Phenacogrammus interruptus — 📷 7TP (Krzysztof Bartosik) · CC BY-SA 4.0 · resized · Wikimedia Commons

About

The Congo tetra is a large, shimmering characin endemic to the central Congo River basin in the Democratic Republic of the Congo, where it roves the mid-water of forested tributaries and marshy pools. Mature males are spectacular, flushing iridescent blue, gold and green along the flank and trailing long, ghostly fin filaments. Peaceful yet easily startled, it needs a long, well-planted tank with open swimming lanes and a proper shoal to feel secure and show its best colour.

Care

Keep a mixed-sex shoal of 6+ in a long tank of at least 110 L with soft, slightly acidic water, gentle current and open swimming space. Skittish, so avoid boisterous or fin-nipping tankmates and provide a secure lid.

Diet

Hearty omnivore; feed a staple of quality flakes and pellets supplemented with frequent frozen and live meaty foods to bring out colour and fin development.

Tankmate compatibility

Computed by the AquaSage engine for a spacious reference tank — always check the full verdict for your exact setup in the calculator.

Full tank-mates guide with reasons →

Telling males from females

What works for this species, most reliable first.

Belly depthA hint only · only on well-fed adults, and only as a comparison
For most tetras, barbs and rasboras this is all there is: a conditioned female is deeper through the belly than a male of the same length.

All the methods, with diagrams

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Frequently asked questions

What tank size does a Congo Tetra need?: A Congo Tetra needs an aquarium of at least 110 litres (29.1 US gallons) with a footprint at least 120 cm (47.2 in) long — for this species, swimming length matters as much as raw volume.
What water parameters does a Congo Tetra need?: Congo Tetra does best at 23–28 °C (73.4–82.4 °F), pH 6–7.5 and a general hardness of 3–18 °dGH.
What group size does a Congo Tetra need?: Congo Tetra is a social species — keep a group of at least 6 so natural behaviour emerges and stress stays low.
Is the Congo Tetra suitable for beginners?: Congo Tetra sits in the middle of the difficulty scale — manageable for a careful beginner who has done the reading, but it has specific needs worth researching first.

Sources

Water & tank

Temperature23–28°C

Optimal temp.24–27°C

pH6–7.5

Hardness (GH)3–18°d

Carbonate (KH)1–12°d

Adult size8.5 cm

Min. volume≥ 110 L

Min. tank length≥ 120 cm

Group size≥ 6

Swimming zoneMid

TemperamentPeaceful

Water typeFreshwater

FlowModerate

Lifespan~5 yrs

Try in the calculator