Can Guppy live with Rummy-nose tetra?

Temperature. Guppy does best at 18–28 °C (64–82 °F) and Rummy-nose tetra at 24–27 °C (75–81 °F). They share 24–27 °C.

Water. Their pH ranges overlap at 7–7.

Temperament and size. Guppy is peaceful and grows to 6 cm; Rummy-nose tetra is peaceful and grows to 5 cm. Guppy swims at the top and Rummy-nose tetra at the mid, which spreads them out.

Tank size and groups. Plan on at least 20 US gallons, the larger of the two cautious minimums. Keep Guppy in a group of 3+. Keep Rummy-nose tetra in a group of 10+. A starter mix of 3 Guppy and 10 Rummy-nose tetra in 20 gallons uses about 98% 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.
• Shrimp and snails: neither is a known invertebrate eater, but baby shrimp can still be eaten. Dense moss helps.
• 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

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.