FaunaHub

Betta Fish (Betta splendens)

FishFreshwaterAquarium

A male Siamese fighting fish (Betta splendens) with long flowing red-and-blue fins.

Male betta / Siamese fighting fish (Betta splendens).

Image: Daniella Vereeken, CC BY 2.0, via Wikimedia Commons.

Overview

The betta, or Siamese fighting fish (Betta splendens), is a small freshwater fish native to Southeast Asia and one of the most popular aquarium fish in the world. Males are famous for their vivid colours and long, flowing fins. Bettas are "labyrinth fish", able to breathe air at the surface using a special organ, which lets them survive in warm, low-oxygen waters in the wild.

Habitat & Range

In the wild, bettas live in the warm, shallow, often slow-moving or still fresh waters of Southeast Asia, such as rice paddies, floodplains, and marshes. These habitats are warm and densely vegetated. The image of a betta thriving in a tiny unheated bowl is a myth: in captivity they need an appropriately sized, heated, and filtered aquarium, and requirements should be confirmed with qualified aquarium guidance.

Diet

Bettas are carnivorous and, in the wild, feed largely on small invertebrates such as insect larvae and zooplankton. In aquariums they are fed prepared foods formulated for carnivorous fish. This page does not give feeding quantities; appropriate diet and amounts depend on the individual fish and should follow qualified aquarium advice.

Behavior

Male bettas are highly territorial toward other males — the source of the name "fighting fish" — and two males should not be housed together. They will flare their gills and fins in display. Bettas can be interactive and are often described as having individual personalities. As surface-breathers, they regularly rise to gulp air. Behaviour and compatibility with other fish vary, so tank-mate decisions should be made cautiously.

Human Interaction & Conservation

Bettas have been kept and selectively bred for centuries, producing the many colours and fin types seen today. They are aquarium animals, not wildlife to be released, and releasing aquarium fish into local waters can cause ecological harm. Responsible keeping means a properly heated, filtered, and sized aquarium, suitable water quality, and access to qualified help if a fish appears unwell. This profile is educational and is not a substitute for aquarium-care or veterinary guidance.

Appearance & Recognition

Bettas are small fish, but captive-bred males are unmistakable, with long, trailing fins and intense colours ranging from deep blues and reds to multicolour patterns. Females are generally smaller with shorter fins and less dramatic colour. Many fin types have been bred — such as veiltail, halfmoon, and crowntail — but all are the same species. The upturned mouth reflects their surface-feeding habits.

Similar Animals

Bettas are part of the gourami family (Osphronemidae) and share the labyrinth-breathing adaptation with other gouramis. Among the aquarium fish covered on FaunaHub, the guppy is another popular small freshwater species, though it is a livebearer with very different care and temperament.

Betta fish care basics →Aquarium care hub →

More photos of the betta fish

A male betta fish displaying its fins in an aquarium.

A male betta displaying its fins.

Image: Daniella Vereeken, CC BY 2.0, via Wikimedia Commons.

Frequently Asked Questions — Betta Fish

Can a betta live in a small bowl?
No. The idea that bettas thrive in tiny unheated bowls is a myth. Like other aquarium fish, bettas need an appropriately sized, heated, and filtered aquarium with good water quality. Specific tank size and setup should follow qualified aquarium guidance rather than marketing.
Why are male bettas kept alone?
Male bettas are territorial and will fight other males, which is why two males are not housed together. Compatibility with other species and with females is situation-dependent and should be researched carefully before adding tank mates.
How do bettas breathe air?
Bettas are labyrinth fish: they have an organ that lets them take oxygen from air gulped at the surface, in addition to using their gills. This adaptation suits the warm, low-oxygen waters of their native habitat, but it does not mean they can live without clean, well-maintained water.

Sources and further reading

Authoritative wildlife references used for general educational context. Conservation status should always be verified against current IUCN Red List data. External links open in a new tab.