Family: Osphronemidae
A flamboyant labyrinth fish from Southeast Asia; males are famously territorial and long-finned.
Bred for centuries in Thailand for fighting prowess, then for impossible fins. A heated, calm, well-planted tank turns it into living stained glass. Males must live alone.
No. Male bettas fight to serious injury or death. The famous exception of large, heavily divided 'sorority-style' male display tanks belongs to specialists; the safe rule is one male per tank.
Almost always water quality or temperature. Test ammonia and nitrite, verify the heater, and increase water changes. Fin rot in clean warm water usually heals without medication.
Yes, for a long and healthy life. A gentle sponge filter and a reliable heater turn a two-year fish into a five-year fish. Cups and bowls are display vessels, not homes.
Carefully chosen tankmates work: snails, shrimp (though some bettas hunt them), and calm fish that neither nip flowing fins nor outcompete the betta for food. Avoid fin-nippers like tiger barbs and flashy fish the betta will attack.
Bright color, erect fins, clear eyes, and immediate interest in you — a betta that flares or follows your finger is a betta with spirit and usually with health.