Yes: Compatible.
No clashes under our rules: they share a temperature range, neither is a fin nipper or predator of the other, and their temperaments fit.
Temperature. Neon tetra does best at 21–25 °C (70–77 °F) and Rummy-nose tetra at 24–27 °C (75–81 °F). They share 24–25 °C.
Water. Their pH ranges overlap at 5.5–7.
Temperament and size. Neon tetra is peaceful and grows to 3 cm; Rummy-nose tetra is peaceful and grows to 5 cm. Both use the mid of the tank, so give them room and cover.
Tank size and groups. Plan on at least 20 US gallons, the larger of the two cautious minimums. Keep Neon tetra in a group of 8+. Keep Rummy-nose tetra in a group of 10+. A starter mix of 8 Neon tetra and 10 Rummy-nose tetra in 20 gallons uses about 96% of the tank’s bioload capacity under our rules and grades A.
Keeping them together
- Feeding: both feed in open water. Feed small amounts two or three times a day so the slower eater gets its share.
- Aquascape: both are calmer with cover. Plants and floating cover make shy fish come out more, not less.
- Group size: a full group is not optional. A schooling fish kept in too small a group is stressed and more likely to nip or hide.
- Adding them: add the calmer species first and let it settle for a week or two before adding the other, and only once your tank has cycled.
Open this pair in the checker Add your other fish to grade the whole tank.
Quick facts
| Neon tetra | Rummy-nose tetra | |
|---|---|---|
| Adult size | 3 cm | 5 cm |
| Min tank | 15 gal | 20 gal |
| Temperature | 21–25 °C | 24–27 °C |
| pH | 5–7 | 5.5–7 |
| Temperament | peaceful | peaceful |
| Group size | 8+ | 10+ |
Data from the Species Ledger, checked November 9, 2026, with at least two sources per species. Cautious community guidelines, not guarantees: individual fish vary. Not veterinary advice. Disagree? Tell us.