Betta splendens, also known as the betta, is a popular fish in the aquarium trade. This species is native to the Mekong basin of Thailand, Cambodia, Laos, and Vietnam and is mostly concentrated in the Chao Phraya river in Thailand. The fish can be found in standing waters of canals, rice paddies and floodplains.
Bettas are a member of the gourami family and are known to be highly territorial. Males in particular are prone to high levels of aggression and will attack each other if housed in the same tank. If there is no means of escape, this will usually result in the death of one or both of the fish. Female bettas can also become territorial towards each other if they are placed in too small an aquarium. It is typically not recommended to keep male and female bettas together, except temporarily for breeding purposes which should always be undertaken with caution.
B. splendens usually grows to a length of about 2.8 in. Although aquarium specimens are widely known for their brilliant colors and large, flowing fins, the natural coloration of B. splendens is generally green, brown and grey, and the fins of wild specimens are short. In the wild, they exhibit strong colors only when agitated. In captivity, they have been selectively bred to display a vibrant array of colors and tail types. Some bettas will change colours throughout their lifetime (known as marbling).
Betta splendens feed on zooplankton, crustaceans, and the larvae of mosquitoes and other water-bound insects. In captivity they can be fed a varied diet of pellets or frozen foods such as brine shrimp, bloodworms, daphnia and many others.
Betta species prefer a water temperature of around 75–82 °F. When kept in colder climates, aquarium heaters are recommended. Bettas are also affected by the pH levels of the water. Ideal levels for Bettas would be at a neutral pH (7.0) However, Bettas are slightly tolerant towards the pH levels. They have an organ known as the labyrinth organ which allows them to breathe air at the water’s surface. This organ was thought to allow the fish to be kept in unmaintained aquaria, but this is a misconception, as poor water quality makes all tropical fish, including Betta splendens, more susceptible to diseases such as fin rot. Reliably performing regular partial water changes (every other day for small unfiltered tanks) would at least ensure the water quality in a smaller tank is acceptable.
Bettas can cohabit with fish that are bottom feeders, however it is not advised to keep them with feeders that may eat their fins or destroy the slime coat (one example is the Siamese Algae Eater, if kept in an inappropriately sized tank)
Properly kept and fed a correct diet, Siamese fighting fish generally live between 3 and 5 years in captivity, but may live between 7 and 10 years in rare cases.