Photo: Radomil (CC BY-SA 3.0) — via Wikimedia Commons
Congo Tetra (Phenacogrammus interruptus)
A shimmering, rainbow-scaled tetra from the Congo River basin — males grow flowing, streamer-like fins that make them one of the most spectacular schooling fish in the freshwater hobby.
Will it live with a Congo Tetra?
We compare each fish against your congo tetra on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- Amazon Puffer✅ CompatiblePeaceful · 8 cm · Medium care · 23–28 °C (73–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Amazon Puffer in a shoal of 6+ or it gets stressed and nippy.
- Ash Lipped Apisto✅ CompatibleSemi-aggressive · 7 cm · Hard care · 24–29 °C (75–84 °F)
- Peaceful + Semi-aggressive, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Banded Dwarf Cichlid✅ CompatibleSemi-aggressive · 7 cm · Medium care · 24–30 °C (75–86 °F)
- Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Black Kuhli Loach✅ CompatiblePeaceful · 8 cm · Easy care · 23–28 °C (73–82 °F)
- Both are peaceful, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Bleeding Heart Tetra✅ CompatibleSemi-aggressive · 7 cm · Medium care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Bleeding Heart Tetra in a shoal of 6+ or it gets stressed and nippy.
- Bolivian Ram✅ CompatiblePeaceful · 8 cm · Medium care · 24–28 °C (75–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Bright Diamond Tetra✅ CompatiblePeaceful · 7 cm · Hard care · 24–28 °C (75–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Bright Diamond Tetra in a shoal of 8+ or it gets stressed and nippy.
- Brilliant Rasbora✅ CompatiblePeaceful · 9 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Brilliant Rasbora in a shoal of 6+ or it gets stressed and nippy.
- Buenos Aires Tetra✅ CompatibleSemi-aggressive · 7 cm · Easy care · 18–26 °C (64–79 °F)
- Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Buenos Aires Tetra in a shoal of 6+ or it gets stressed and nippy.
- Burmese Loach✅ CompatiblePeaceful · 9 cm · Easy care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Celebes Rainbowfish✅ CompatiblePeaceful · 7 cm · Medium care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Celebes Rainbowfish in a shoal of 6+ or it gets stressed and nippy.
- Clown Pleco✅ CompatiblePeaceful · 9 cm · Medium care · 24–28 °C (75–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Costa's Tetra✅ CompatiblePeaceful · 7 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Costa's Tetra in a shoal of 6+ or it gets stressed and nippy.
- Croaking Gourami✅ CompatiblePeaceful · 7 cm · Easy care · 24–28 °C (75–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Glass Catfish✅ CompatiblePeaceful · 8 cm · Medium care · 23–28 °C (73–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Glass Catfish in a shoal of 6+ or it gets stressed and nippy.
- Gold Barb✅ CompatiblePeaceful · 7.5 cm · Easy care · 18–26 °C (64–79 °F)
- Both are peaceful, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Gold Barb in a shoal of 6+ or it gets stressed and nippy.
- Hongsloi Dwarf Cichlid✅ CompatibleSemi-aggressive · 7 cm · Medium care · 24–29 °C (75–84 °F)
- Peaceful + Semi-aggressive, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Leopard Frog Pleco✅ CompatiblePeaceful · 9 cm · Medium care · 25–30 °C (77–86 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Pantanal Corydoras✅ CompatiblePeaceful · 8 cm · Medium care · 22–27 °C (72–81 °F)
- Both are peaceful, and their water overlaps around 22–27 °C — no size, zone or temperament conflicts.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Pantanal Corydoras in a shoal of 6+ or it gets stressed and nippy.
- Scissortail Rasbora✅ CompatiblePeaceful · 8 cm · Easy care · 22–27 °C (72–81 °F)
- Both are peaceful, and their water overlaps around 22–27 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Scissortail Rasbora in a shoal of 6+ or it gets stressed and nippy.
- Silver Tetra✅ CompatiblePeaceful · 9 cm · Easy care · 24–28 °C (75–82 °F)
- Both are peaceful, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Silver Tetra in a shoal of 6+ or it gets stressed and nippy.
- Splashing Tetra✅ CompatiblePeaceful · 8 cm · Medium care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Splashing Tetra in a shoal of 6+ or it gets stressed and nippy.
- Thick-lipped Gourami✅ CompatiblePeaceful · 9 cm · Easy care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the middle of the tank — offer enough cover so they aren't always in each other's space.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Zebra Loach✅ CompatiblePeaceful · 9 cm · Medium care · 23–26 °C (73–79 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Afra Cichlid⚠️ With cautionSemi-aggressive · 10 cm · Medium care · 24–28 °C (75–82 °F)
- Different pH ranges (6–7.5 vs 7.8–8.6); doable if you sit in the shared band, but not ideal long-term.
- Afra Cichlid is semi-aggressive and may chase or nip the smaller Congo Tetra — plant heavily and break up sight lines.
- Your 120 L tank is below the ~150 L this pairing really wants — crowding raises aggression.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Afra Cichlid in a shoal of 6+ or it gets stressed and nippy.
- African Butterfly Cichlid⚠️ With cautionSemi-aggressive · 8 cm · Medium care · 22–28 °C (72–82 °F)
- Expect African Butterfly Cichlid to harass Congo Tetra at times; give dense cover and watch them at feeding.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Agassiz's Dwarf Cichlid⚠️ With cautionSemi-aggressive · 9 cm · Medium care · 24–30 °C (75–86 °F)
- Agassiz's Dwarf Cichlid and Congo Tetra are close in size, but the semi-aggressive one tends to dominate — add congo tetra in a group to spread the pressure.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Badis⚠️ With cautionSemi-aggressive · 8 cm · Medium care · 22–28 °C (72–82 °F)
- Badis and Congo Tetra are close in size, but the semi-aggressive one tends to dominate — add congo tetra in a group to spread the pressure.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Bamboo Shrimp⚠️ With cautionPeaceful · 8 cm · Medium care · 22–27 °C (72–81 °F)
- Congo Tetra may eat Bamboo Shrimp or pick off its shrimplets — a densely planted tank with moss gives them a fighting chance.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Bandit Cichlid⚠️ With cautionSemi-aggressive · 9 cm · Medium care · 22–26 °C (72–79 °F)
- Bandit Cichlid is semi-aggressive and may chase or nip the smaller Congo Tetra — plant heavily and break up sight lines.
- Your 120 L tank is below the ~150 L this pairing really wants — crowding raises aggression.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Bandit Cichlid in a shoal of 6+ or it gets stressed and nippy.
- Brichardi Cichlid⚠️ With cautionSemi-aggressive · 9 cm · Medium care · 24–28 °C (75–82 °F)
- Different pH ranges (6–7.5 vs 7.8–9); doable if you sit in the shared band, but not ideal long-term.
- Expect Brichardi Cichlid to harass Congo Tetra at times; give dense cover and watch them at feeding.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Cockatoo Dwarf Cichlid⚠️ With cautionSemi-aggressive · 8 cm · Medium care · 24–28 °C (75–82 °F)
- Expect Cockatoo Dwarf Cichlid to harass Congo Tetra at times; give dense cover and watch them at feeding.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Convict Cichlid⚠️ With cautionAggressive · 10 cm · Easy care · 21–28 °C (70–82 °F)
- Expect Convict Cichlid to harass Congo Tetra at times; give dense cover and watch them at feeding.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Daffodil Cichlid⚠️ With cautionSemi-aggressive · 10 cm · Medium care · 23–27 °C (73–81 °F)
- pH preferences only just meet (Congo Tetra 6–7.5 vs Daffodil Cichlid 7.8–9) — target the overlap and acclimate slowly.
- Daffodil Cichlid is semi-aggressive and may chase or nip the smaller Congo Tetra — plant heavily and break up sight lines.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Demasoni Cichlid⚠️ With cautionAggressive · 9 cm · Hard care · 23–27 °C (73–81 °F)
- Different pH ranges (6–7.5 vs 7.8–8.6); doable if you sit in the shared band, but not ideal long-term.
- Demasoni Cichlid is aggressive and may chase or nip the smaller Congo Tetra — plant heavily and break up sight lines.
- Your 120 L tank is below the ~200 L this pairing really wants — crowding raises aggression.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Demasoni Cichlid in a shoal of 12+ or it gets stressed and nippy.
- Dwarf Gourami⚠️ With cautionSemi-aggressive · 8 cm · Medium care · 24–28 °C (75–82 °F)
- Dwarf Gourami and Congo Tetra are close in size, but the semi-aggressive one tends to dominate — add congo tetra in a group to spread the pressure.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Electric Yellow Cichlid⚠️ With cautionSemi-aggressive · 10 cm · Medium care · 23–26 °C (73–79 °F)
- Different pH ranges (6–7.5 vs 7.8–8.9); doable if you sit in the shared band, but not ideal long-term.
- Electric Yellow Cichlid and Congo Tetra are close in size, but the semi-aggressive one tends to dominate — add congo tetra in a group to spread the pressure.
- Your 120 L tank is below the ~200 L this pairing really wants — crowding raises aggression.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Goldeneye Dwarf Cichlid⚠️ With cautionSemi-aggressive · 8 cm · Easy care · 24–28 °C (75–82 °F)
- Expect Goldeneye Dwarf Cichlid to harass Congo Tetra at times; give dense cover and watch them at feeding.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Lifalili Jewel Cichlid⚠️ With cautionAggressive · 9 cm · Medium care · 22–28 °C (72–82 °F)
- Expect Lifalili Jewel Cichlid to harass Congo Tetra at times; give dense cover and watch them at feeding.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Mexican Tetra⚠️ With cautionSemi-aggressive · 9 cm · Easy care · 18–25 °C (64–77 °F)
- Mexican Tetra is semi-aggressive and may chase or nip the smaller Congo Tetra — plant heavily and break up sight lines.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Keep Mexican Tetra in a shoal of 6+ or it gets stressed and nippy.
- Alligator Gar⛔ Not recommendedAggressive · 250 cm · Hard care · 24–28 °C (75–82 °F)
- Congo Tetra is bite-sized to a 250 cm predatory alligator gar — it will be eaten.
- Alligator Gar is aggressive and may chase or nip the smaller Congo Tetra — plant heavily and break up sight lines.
- Your 120 L tank is below the ~3785 L this pairing really wants — crowding raises aggression.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Clown Knifefish⛔ Not recommendedAggressive · 90 cm · Hard care · 24–28 °C (75–82 °F)
- Clown Knifefish (90 cm) is big enough to swallow the 8 cm Congo Tetra whole.
- Expect Clown Knifefish to harass Congo Tetra at times; give dense cover and watch them at feeding.
- Your 120 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Fire Eel⛔ Not recommendedSemi-aggressive · 100 cm · Medium care · 24–28 °C (75–82 °F)
- Fire Eel (100 cm) is big enough to swallow the 8 cm Congo Tetra whole.
- Expect Fire Eel to harass Congo Tetra at times; give dense cover and watch them at feeding.
- Your 120 L tank is below the ~380 L this pairing really wants — crowding raises aggression.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Koi⛔ Not recommendedPeaceful · 90 cm · Medium care · 4–28 °C (39–82 °F)
- Size gap is too large (90 vs 8 cm): Koi will treat Congo Tetra as food.
- Your 120 L tank is below the ~3800 L this pairing really wants — crowding raises aggression.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Redtail Catfish⛔ Not recommendedAggressive · 120 cm · Hard care · 24–27 °C (75–81 °F)
- Redtail Catfish (120 cm) is big enough to swallow the 8 cm Congo Tetra whole.
- Redtail Catfish is aggressive and may chase or nip the smaller Congo Tetra — plant heavily and break up sight lines.
- Your 120 L tank is below the ~5700 L this pairing really wants — crowding raises aggression.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Spotted Gar⛔ Not recommendedAggressive · 90 cm · Hard care · 18–26 °C (64–79 °F)
- Congo Tetra is bite-sized to a 90 cm predatory spotted gar — it will be eaten.
- Expect Spotted Gar to harass Congo Tetra at times; give dense cover and watch them at feeding.
- Your 120 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Wels Catfish⛔ Not recommendedAggressive · 300 cm · Hard care · 15–25 °C (59–77 °F)
- Congo Tetra is bite-sized to a 300 cm predatory wels catfish — it will be eaten.
- Expect Wels Catfish to harass Congo Tetra at times; give dense cover and watch them at feeding.
- Your 120 L tank is below the ~20000 L this pairing really wants — crowding raises aggression.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
- Wolf Cichlid⛔ Not recommendedAggressive · 72 cm · Hard care · 24–30 °C (75–86 °F)
- Wolf Cichlid (72 cm) is big enough to swallow the 8 cm Congo Tetra whole.
- Expect Wolf Cichlid to harass Congo Tetra at times; give dense cover and watch them at feeding.
- Your 120 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
- Keep Congo Tetra in a shoal of 6+ or it gets stressed and nippy.
Compatibility is computed from each species' care data — a strong starting point, not a guarantee. Individual temperament varies, so always introduce new fish slowly and watch them.
Congo Tetra care specs
- Care level
- Medium
- Breeding
- Hard
- Max size
- 8 cm (3.1 in)
- Min tank size
- 120 L (31.7 gal)
- Temperature
- 22–28 °C (72–82 °F)
- pH
- 6–7.5
- Hardness
- 2–15 dGH
- Lifespan
- 3–5 years
- Diet
- Omnivore
- Swim level
- Middle
- Group size
- 6+ (shoaling)
- Family
- Alestidae
- Origin
- Congo River basin, Democratic Republic of the Congo
What is a Congo Tetra?
The Congo Tetra (Phenacogrammus interruptus) is one of freshwater fishkeeping’s genuine showpieces. Where most tetras top out at 3–4 cm, males of this species reach a full 8 cm (3.1 in), dressed in iridescent blue-green flanks crossed by a warm orange-gold mid-stripe that shifts colour as the fish moves through the water. Add the flowing, filamentous extensions on the dorsal and caudal fins that mature males develop, and you have a schooling fish with real presence.
Despite the dramatic looks, the Congo Tetra is peaceful and community-minded. It shoals closely in the middle water column and is at its best in a group where males can display alongside one another — colour and finnage intensifying in the mild social competition of the shoal.
Where do Congo Tetras come from?
Congo Tetras are native to the Congo River basin in the Democratic Republic of the Congo. In the wild they inhabit warm, slow-moving tributaries, flooded forest margins and backwater pools where the water is characteristically soft, slightly acidic and tannin-stained — amber from decaying leaf litter, low in dissolved minerals.
That origin matters for care. A Congo Tetra in soft, warm, slightly acidic water in a planted tank shows its full colour; one in hard, alkaline water with bright bare substrate looks dull and stressed. The market fish are nearly all aquacultured and therefore more adaptable, but they still respond clearly to water conditions that resemble home.
What size tank does a Congo Tetra need?
The minimum is 120 litres (about 32 gallons), and footprint matters as much as volume. Congo Tetras school in long, sweeping mid-water arcs, so a tank at least 100 cm (39 in) in length suits them far better than a tall, narrow one of equal volume.
Plant the back and sides densely with taller stems and some floating cover for shade and security, and leave a clear lane through the middle for the shoal to swim. A dark substrate — fine black or brown sand or gravel — makes the iridescent flanks pop and reduces stress from reflected light. Filtration should produce gentle to moderate flow; keep the tank well-oxygenated and use a tight-fitting lid — Congo Tetras jump.
What water parameters do Congo Tetras need?
- Temperature: 22–28 °C (72–82 °F). The sweet spot for long-term health and colour is 24–26 °C (75–79 °F).
- pH: 6.0–7.5. Softer, slightly acidic water (pH 6.5–7.0) produces the best colour and behaviour.
- Hardness: 2–15 dGH. They prefer soft water; hardness above 15 dGH noticeably dulls their colour over time.
Cycle the tank fully before adding fish, and maintain weekly partial water changes of around 20–25%. Congo Tetras are sensitive to rising nitrates — not dramatically fragile, but they will show it in faded colour and reduced activity before anything else. Avoid sudden parameter swings; stable water chemistry within the acceptable range is more important than hitting a precise target.
What do Congo Tetras eat?
Congo Tetras are omnivores that accept a wide range of foods. A high-quality flake or small micro-pellet works as a daily staple; supplement several times a week with small live or frozen foods — brine shrimp, daphnia and bloodworm are all taken eagerly.
Feed small portions two to three times a day and remove uneaten food promptly. Congo Tetras come from clean, well-oxygenated water and are sensitive to the nitrate spike that decaying food causes. Regular protein supplements also deepen colour saturation, particularly in competing males.
Are Congo Tetras aggressive — and what fish can live with them?
Congo Tetras are peaceful toward other species. Within the group, males engage in low-level display — flaring fins and jostling for position — but this rarely escalates and is healthy shoal behaviour. A ratio of roughly two females to each male spreads the males’ attention and prevents any one female from being persistently pursued.
Where Congo Tetras need protecting is from other fish’s aggression: those spectacular fins are a magnet for fin-nippers. Avoid tiger barbs, serpae tetras and other known nippers. Ideal companions are peaceful mid- to upper-water fish of similar size — rummy nose tetras, emperor tetras, peaceful rasboras — plus calm bottom-dwellers like corydoras. Skip territorial cichlids and boisterous species that outcompete them at feeding.
For a full breakdown of tested pairings, see Congo Tetra tank mates.
How do you tell male and female Congo Tetras apart?
Dimorphism in Congo Tetras is pronounced and visible from across the tank. Males reach up to 8 cm (3.1 in) and develop the species’ signature finnage: elongated, filamentous extensions on the dorsal fin trailing backward, and a central pointed extension on the caudal fin. Their colouration is intense — a vivid orange-gold mid-stripe and strong iridescent sheen on the flanks.
Females are smaller, typically 5–6 cm (2–2.4 in), with a rounder, deeper body profile (especially when carrying eggs), shorter conventional fins, and a softer golden-yellow tone. In a healthy mature group the difference is obvious; in juveniles it takes a few months to become clear.
How do Congo Tetras breed?
Congo Tetras are egg-scatterers, but breeding in captivity earns a hard rating. Accidental spawning in a community tank rarely produces surviving fry — eggs and young are quickly eaten by tankmates and parents alike.
For intentional breeding, set up a separate spawning tank of around 60–80 L (15–20 gal) with very soft, slightly acidic water (pH 6.0–6.5, 1–4 dGH) at 26–27 °C (79–81 °F). Line the base with fine mesh or java moss to protect eggs. Condition a small group of adults with live and frozen foods for a couple of weeks, then move one or two pairs to the spawning tank in the evening. Spawning typically occurs in the morning; remove the adults immediately after. Keep the tank dim — the eggs are light-sensitive. Fry become free-swimming after several days and need infusoria or commercial fry food before graduating to baby brine shrimp.
What are common Congo Tetra diseases?
Congo Tetras are not unusually disease-prone, but they share the vulnerabilities of most tetras. The most common issues are:
- Ich (white spot disease): Small white cysts on the body and fins, caused by the parasite Ichthyophthirius multifiliis. Most often triggered by temperature drops or stress from poor water quality. Raise the temperature gradually and maintain excellent water conditions as a first step.
- Fin rot: Ragged, receding fin edges, almost always a secondary consequence of bacterial infection in degraded water. Improving water quality and reducing bioload resolves mild cases; persistent fin rot points to an underlying water management problem.
- Velvet (Oodinium): A fine gold or rust-coloured dusting on the body, most visible under a torch held at a low angle. Highly contagious; quarantine affected fish promptly.
- Internal parasites: Wild-caught specimens may carry internal worms; aquacultured stock is a lower risk but quarantine new arrivals regardless.
Prevention covers all of these: a cycled, stable tank, weekly water changes, a varied diet and a proper quarantine period for any new fish before they join the main tank. Avoid sudden temperature swings, which stress the immune system.
Health note: disease diagnosis and medication dosing are beyond the scope of a care profile. If your fish are showing symptoms, confirm the diagnosis against a reputable veterinary or fish-health source before medicating — and always treat in a separate quarantine tank where possible.
How long do Congo Tetras live?
With good care, Congo Tetras live 3–5 years — consistent with most medium-sized tetras. Fish kept in hard water, with fluctuating temperatures or in a group too small rarely reach the upper end of that range. A cycled, planted tank with a shoal of six or more, stable soft-water parameters and a varied diet gives them the best chance of hitting five years — and showing their best colour throughout.
Frequently asked questions
How many Congo Tetras should I keep together?
Keep a minimum of six, and eight or more is better. In smaller numbers they become skittish, lose colour intensity, and males can pester each other. A ratio of two females per male helps spread male attention. Their sheer size — males can hit 8 cm — means the group also needs a genuinely long tank with open mid-water swimming lanes.
Why do Congo Tetras look washed out in my tank?
The iridescent sheen needs good lighting at the right angle and a dark substrate or background to really pop. Stress from a group that's too small, overly bright lighting, or water parameters outside their comfort zone (especially pH creeping above 7.5 or hardness above 15 dGH) will dull their colours fast. Warm, soft, slightly acidic water and a well-established, heavily planted tank bring out the best in them.
What you need to keep a congo tetra
The baseline is a heated, filtered 120 L+ tank: a reliable heater to hold 22–28 °C (72–82 °F), a gentle filter that won't batter a congo tetra in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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