Species · Tetras & rasboras
Rummynose Tetra
Hemigrammus rhodostomus
The elegant tight-shoaling tetra whose bright red nose doubles as a living water-quality gauge — it fades when the water is off. Keep a real group in a mature, soft-water tank.
Difficulty: Beginner–Intermediate Tropical community tank ✓ Fact-checked care guide
Quick facts
| Adult size | ~5 cm / 2 in |
|---|---|
| Minimum tank | ~60 L / 15 US gal for a proper shoal (a strong shoaler that wants room) |
| Temperature | 24–27 °C / 75–81 °F |
| pH | 5.5–7.0 (soft, acidic to neutral) |
| Hardness | 2–15 dGH (soft to moderately soft) |
| Filtration & flow | Cycled, gentle-to-moderate filtration; needs a mature, stable tank |
| Diet | Micro-omnivore — small flake/micro-pellet plus tiny live/frozen foods |
| Social | A true tight-shoaling fish — keep at least 8–10 |
| Temperament | Very peaceful |
| Lifespan | 5–6 years |
Overview
The rummynose tetra (Hemigrammus rhodostomus) is prized for two things: it schools more tightly than almost any other tetra, and its vivid red nose is a built-in water-quality meter — it fades when conditions slip and glows when they're right.
A quick honest note: the fish sold as "rummynose" is often the very similar firehead tetra (H. bleheri) or the false rummynose — care is essentially the same, so don't worry which you have.
💷 Costing it out? See how much a rummynose tetra really costs to keep — the rummynose tetra itself is usually the cheapest part.
Water & tank
Rummynose want soft, acidic-to-neutral water (pH 5.5–7.0, 2–15 dGH) at 24–27 °C / 75–81 °F, and — because the red nose reflects water quality — they especially reward a clean, mature, stable tank. Add them to a fully cycled aquarium, never a new one.
They are strong swimmers that shoal tightly, so give them room — around ~60 L / 15 US gal or more for a proper group, planted, with open swimming space.
Feeding
A micro-omnivore — small flake/micro-pellet plus tiny live/frozen foods for colour and condition. Feed small amounts once or twice a day.
Behaviour & tankmates
Peaceful and best kept in a real group of 8–10+, where the tight schooling is mesmerising. Great with other calm community fish; avoid fin-nippers and large predators.
What to expect
Use the nose as your gauge: bright red = happy, healthy water; a faded or pale nose means test the water and do a change. Tight, coordinated schooling is the reward for getting the water right.
Myths, kindly busted
“A dull rummynose nose is just its natural colour.”
A faded nose is often a water-quality signal — test the water; the colour usually returns once conditions improve.
“You must buy the "true" rummynose.”
Three near-identical species are sold under the name; care is the same, so it doesn't matter which you get.
🐟 Did you know? — Rummynose Tetra fun facts
Little true delights about the rummynose tetra — each one checked against a named source, no pet-shop myths.
- The name rhodostomus is Greek for “red mouth”, for the fish's glowing red nose and face. SeriouslyFish
- The red “blush” is a health tell: the rummynose loses its colour in unfavourable or alkaline water, so a faded nose signals poor conditions. SeriouslyFish
- It is one of the most tightly shoaling small tetras — so much so it does poorly unless kept in groups of ten or more. SeriouslyFish
When to act
We triage, not diagnose — but these are worth a closer look (starting with a water test):
- A faded or greyish nose across the group — a classic water-quality cue; test and do a water change.
- White spots, clamped fins or hiding — test the water and act early; they dislike an immature tank.
Heading to a vet? Print the Rummynose Tetra vet-prep sheet — what to bring, what to tell them, and the questions to ask.
Sources & further reading
- SeriouslyFish — Hemigrammus rhodostomus — Adult ~50 mm SL; temperature 24–27 °C / 75–81 °F (steady heat); pH 5.5–7.0; hardness 2–15 dGH; peaceful shoaling fish; commonly confused with H. bleheri / false rummynose (same care).
Written & fact-checked by The Finfern Team against the sources above — kind, general guidance, not a diagnosis. If something looks wrong, test your water and, if it persists, contact a fish-savvy vet.
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