Can Swordtail live with Zebra danio?

Temperature. Swordtail does best at 22–27 °C (72–81 °F) and Zebra danio at 18–24 °C (64–75 °F). They share 22–24 °C.

Water. Their pH ranges overlap at 7–8.

Temperament and size. Swordtail is semi-aggressive and grows to 14 cm; Zebra danio 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 40 US gallons, the larger of the two cautious minimums. Keep Swordtail in a group of 3+. Keep Zebra danio in a group of 8+. A starter mix of 3 Swordtail and 8 Zebra danio in 40 gallons uses about 77% 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: break up sight lines with plants, wood or rock, and give each fish its own hiding spots. Territorial fish settle faster when they can’t see each other all the time.
• 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.

Better matches for Swordtail

These pass every rule with Swordtail: Betta (male) · Molly · Tiger barb · African butterflyfish · Agassiz's dwarf cichlid · Angelfish · Banjo catfish · Black skirt tetra.

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.