Rummynose Tetra (Hemigrammus rhodostomus)

Hemigrammus rhodostomus, the true Rummynose Tetra, is one of three species sold under the 'rummy nose' name alongside H. bleheri and Petitella georgiae. All share the iconic look — brilliant red head, silver body, and black-and-white horizontal striped tail — but H. rhodostomus is considered the original and was the first to be traded. It originates from the Rio Vaupes and nearby blackwater tributaries in Colombia and northwestern Brazil.

Like all rummy nose tetras, H. rhodostomus forms strikingly tight, synchronized schools that create one of the most mesmerizing displays in the freshwater aquarium. The intensity of the red head acts as a live water quality indicator: bright red signals healthy, well-maintained conditions; pale or faded red indicates stress, poor water quality, or disease.

This species thrives in soft, acidic blackwater conditions with tannins from driftwood, Indian almond leaves, or peat filtration. It is more sensitive to water quality than many other tetras and rewards careful maintenance with brilliant long-lasting coloration. It is a peaceful omnivore compatible with other soft-water South American species.

For the best display, keep in schools of 15 or more in a large planted aquarium. The synchronized schooling behavior becomes increasingly spectacular as group size increases, making this species a jewel of the blackwater biotope aquarium.

Water Parameters: Soft, acidic water: pH 5.5–6.8, temperature 24–28°C, GH 1–8. Tannin-stained water from driftwood and Indian almond leaves is strongly recommended. High sensitivity to nitrates — maintain pristine water quality. Avoid hard or alkaline conditions.

Tank Setup: Minimum 100 liters for a school of 15+. Planted aquarium with dark substrate, driftwood, and gentle filtering light from floating plants. Open swimming space is essential for natural schooling behavior. Gentle to moderate current. Subdued lighting best showcases their coloration.

Feeding: Small omnivores accepting micro flake food, micro pellets, small frozen bloodworm, daphnia, and brine shrimp nauplii. Feed twice daily in small amounts. Varied diet enhances red coloration.

Tankmates: Ideal for South American blackwater biotopes: Cardinal Tetras, Corydoras, Apistogramma, hatchetfish, and pencilfish. Avoid alkaline-water species, large fish, or fin-nippers. Best in species-appropriate planted setups.

Health: Sensitive to water quality. High nitrates cause rapid color fading. Perform 25–30% water changes weekly. Watch for neon tetra disease, ich, and velvet. The red nose is your best real-time health indicator.