This guide covers domestic Betta splendens, not every wild betta species. Prepare the aquarium before acquiring the fish and plan for its adult needs.

A proper aquarium

OATA recommends at least 20 litres for one male. Treat that as a starting recommendation, not proof that any 20-litre container is suitable. Larger aquariums give more room and environmental stability. Use a heater, thermometer and filter with a gentle, adjustable flow. Provide plants, smooth hides and open swimming space; avoid decorations that can tear fins.

Air breathing does not make bowls or vases appropriate homes. Leave access to the surface and an air gap beneath a secure cover.

Water and maintenance

OATA lists 20–28°C and pH 6.0–8.0 for commonly traded bettas. These are guidance ranges, not a reason to allow abrupt fluctuations. Establish biological filtration before adding fish; test rather than relying on clear-looking water. Aim for zero ammonia and nitrite. Use conditioned replacement water and maintain the filter without washing its media under untreated tap water.

Company and enrichment

Keep a male betta individually; never combine males. This beginner guide does not recommend female groups or mixed-sex housing. Plants and hides still matter for a fish living alone. Keep neighbouring males out of direct view.

Feeding and health

Offer a suitable formulated betta food in small portions, following its feeding instructions and removing leftovers. Check appetite, fins, swimming and breathing daily. If behaviour changes or wounds appear, check the water promptly and contact a fish-experienced vet for diagnosis rather than choosing a medicine from a symptom alone.

Sources checked

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