Small adult size does not make a guppy suitable for an unfiltered bowl. Plan the aquarium around the group you will keep, not just the fish visible on purchase day.

Aquarium and water

OATA recommends at least 45 litres for a small group of smaller livebearers; RSPCA Australia gives 50 litres as its general tropical-aquarium minimum. Start planning at 50 litres or more for a small guppy group, with additional space for increasing numbers. Neither figure is a stocking formula.

Use a filter, heater and thermometer, plus plants or smooth cover alongside swimming space. OATA's guppy guidance gives 20–28°C, pH 7.0–8.0 and medium-hard water at 8–18°dH. Check your tap-water hardness before selecting fish; do not assume every tropical community has matching needs.

Company and population

Guppies need companionship. For mixed-sex groups OATA advises at least two females per male to reduce pressure on females. However, these livebearers reproduce readily. Arrange an appropriate plan for young before buying a mixed-sex group; adding fish means reassessing space and filtration. Avoid fin-nipping companions or fish large enough to swallow guppies.

Food and routine care

Provide a suitable quality omnivore flake or granule, including algae-based ingredients, in small portions. Remove surplus food. Establish biological filtration before stocking, keep ammonia and nitrite at zero, and test the water regularly. Condition replacement water and adjust partial water changes to actual test results and stocking.

Observe the fish

Check that each fish eats and swims normally. Clamped fins, unusual breathing, visible lesions or a new loss of appetite merit a water-quality check and advice from a fish-experienced vet. A normal-looking tank is not evidence that its chemistry is safe.

Sources checked

Replacement copy checked on 2026-11-08. This is a source-based editorial review, not independent veterinary review.