Betta (fighting fish)

Freshwater fish with spectacular fins and a territorial character. Males cannot coexist with each other. Easy to raise but often poorly maintained.

Detailed explanation

The Betta Splendens is native to the rice fields and waterholes of South-East Asia. Wild males have short fins and discreet colours. The farmed varieties have huge fins and incredible colours: Halfmoon, Crowntail, Plakat, Dumbo, Galaxy Koi are just some of the available forms.

The myth that Bettas can live in a glass is false and cruel. They survive in stagnant water thanks to the labyrinth (an organ that allows them to breathe atmospheric air) but this does not mean they are doing well. A Betta needs at least 15-20 litres with heater and light filter.

The males are aggressive with each other and fight to the death. Never keep two males together. Females can live together in groups of 5 or more (sorority tanks) but with caution: even among females there are aggressive hierarchies.

The ideal temperature is 24-28°C. They are tropical fish and suffer from the cold. A 25 watt heater is enough for a 20-litre nano.

The water flow must be very weak. The long fins of select Bettas make swimming in a current tiring. A sponge filter with aerator is the best choice.

Aquarium companions must be chosen carefully. No fish with coloured fins (mistakes them with rivals). No fin nippers (Barbus, some Tetras). Good companions: Corydoras, small quiet Tetras, Amano shrimp, snails.

The most common diseases are fin rot (bacterial infection favoured by dirty water), white spots (ictio) and dropsy. The best prevention is clean, warm water.

A well-kept Betta lives 3-5 years. In a glass without heating it rarely exceeds a year.

Reference values by aquarium type

Related terms