Siamese Fighting Fish, Betta splendens Regan 1910

Siamese Fighting Fish, Betta splendens. Source: Dave Wilson / Aquagreen, License: All rights reserved


A very popular aquarium fish known for its brilliant colours and elongate fins that have been developed through selective breeding in captivity. In the wild, Siamese Fighting Fish have relatively short fins and are a dull green, to brown or grey in colour. They are surface air breathers with a specialised labyrinth organ allowing them to gulp air from the surface and survive in waters that are low in dissolved oxygen. 

The species was discovered in large numbers in Fogg Dam in the Northern Territory in January 2014. Although native to Thailand, Vietnam and Cambodia in Southeast Asia, introduced Siamese Fighting Fish are established in the wild in some parts of the world.

Siamese Fighting Fish may pose a significant threat to native fishes, frogs and other native species in these wetlands - through competition, predation and the introduction of diseases.

Cite this page as:
Bray, D.J. 2021, Betta splendens in Fishes of Australia, accessed 03 Dec 2022,

Siamese Fighting Fish, Betta splendens Regan 1910

More Info


Discovered in Fogg Dam and the Adelaide River Floodplain in the Northern Territory in January 2014. Native to Thailand, Vietnam and Cambodia in Southeast Asia. The species now appears widespread along the wetlands adjacent the Adelaide River on the Western side upstream and downstream of the Arnhem Highway.
Siamese Fighting Fish are usually found around the margins of large, heavily vegetated marshes, rice paddies and slow moving streams. They can tolerate water with low dissolved oxygen levels due to air-breathing ability. 


Feeds mostly on small aquatic and terrestrial insects and larvae. 


Males are very territorial and build a bubble nest into which females lay their eggs. He male guards to eggs, carefully ensuring that they remain in the bubble nest. The fry hatch after 24–36 hours, and remain in the nest for several days until they fully absorb their yolk sacs. The labyrinth organ develops and becomes functional after 3-6 weeks, and individuals may attain sexual maturity at 4-5 months.

Species Citation

Betta splendens Regan 1910, Proceedings of the Zoological Society of London 1909(4): 782. Type locality: Mae Nam Chao Phraya (as Menam River), Thailand. 


Bray, D.J. 2021


Atlas of Living Australia

Siamese Fighting Fish, Betta splendens Regan 1910


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Quick Facts

CAAB Code:37453002

Biology:Air breather


Max Size:7 cm TL

Native:Introduced, invasive

Species Image Gallery

Species Maps

CAAB distribution map