Rummynose tetra

Quick facts

Adult size

5 cm

Lifespan

can live up to 6 years; captive average is 4-5

Tank zone

mid

Temperament

peaceful

Difficulty

intermediate

Schooling

recommended 8+ (critical minimum 6, thrives at 12+)

Water parameters

Temperature

24–28°C

pH

5.5 to 7.0

Hardness

2 to 12 dGH

Tank requirements

Minimum volume

110 L

Minimum length

75 cm

Flow

low

Lighting

dim preferred

Substrate

any

Driftwood

preferred

Open swimming room

needed

Feeding

Diet: omnivore, feeds primarily at the mid.

Flake, micro pellets, frozen daphnia, bloodworm, and brine shrimp. Not fussy about food type. Feed small amounts 2-3 times daily. Rummynose tetras are midwater feeders and catch food as it drifts through the water column. Color improves with high-quality food containing carotenoids.

Compatibility

• One of the best community schooling fish. Peaceful, non-nippy, and stays in a tight group.
• Classic tankmate for angelfish, discus, rams, and other South American community fish. The tight schooling behavior is visually spectacular with these centerpiece fish.
• Works with corys, plecos, small gouramis, and other tetras.
• Avoid very aggressive tankmates. Rummynose tetras are not easily stressed but they lose their red coloration when harassed, which defeats the purpose of keeping them.
• Safe with shrimp and snails.

Habitat

Three species are sold as "rummynose tetra": Hemigrammus rhodostomus (true rummynose), H. bleheri (the most common, with the reddest head), and Petitella georgiae (false rummynose). All three have the same care requirements and look nearly identical in the aquarium. The brilliant red nose is the species' defining feature and doubles as a water quality indicator: the red fades to pale pink when the fish is stressed, sick, or in poor water. Groups of 10+ form the tightest, most coordinated schools of any commonly kept tetra. They are the gold standard for schooling behavior in planted tanks and aquascaping displays.

Breeding

Egg scatterer. Difficult to breed compared to most tetras. Requires very soft acidic water (pH below 6.0, GH below 3) and dim lighting. Condition breeding pairs with frozen food for two weeks. Spawning usually occurs at dawn. Eggs are scattered among fine-leaved plants and are light-sensitive. Remove adults immediately after spawning. Fry hatch in 24-36 hours and need infusoria for the first few days. The difficulty and specific water requirements mean most rummynose tetras in the trade are wild-caught from Brazil.

Common problems

The red nose fading is the most asked-about issue. It's a reliable stress indicator: pale nose = something wrong. Check ammonia, nitrite, temperature, and look for signs of harassment from tankmates. In a healthy established tank, the red should be vivid and extend well past the eye. Newly purchased rummynose almost always have a pale nose from transport stress; the color returns within a few days if conditions are good. Ich is common in new arrivals. Rummynose tetras need warm water (25–28°C) and stable conditions; they don't tolerate temperature swings well.

Bioload

Bioload coefficient: 1.5 (5 cm body but very active swimmer; pulled down from formula (~2.3) to account for slim body shape).

Bioload coefficients are calibrated against the neon tetra as the anchor (1.0). See the methodology page for the formula and how each value was derived.

Further reading

• Stocking ideas by tank size