--- title: "Siamese Fighting Fish (Betta splendens) | AnimalTracks.wiki" description: "A fish up to 6.5 cm long that breathes air through a labyrinth organ, and whose males flare their gill covers at each other." image: "https://animaltracks.wiki/images/animals/siamese-fighting-fish-1.webp" published: "2026-10-10" updated: "2026-10-11" --- # Siamese Fighting Fish (*Betta splendens*) > **Status**: Checked against 7 sources, listed under Sources below. > **Tagline**: A fish up to 6.5 cm long that breathes air through a labyrinth organ, and whose males flare their gill covers at each other. > **Soundtrack Vibe**: Art Pop & Baroque Pop // Imogen Heap, "Hide and Seek" > **Soundtrack Links**: [Spotify](https://open.spotify.com/track/0904cqduzhGIS9llPW6ksT) > **Vibe Match**: A betta's labyrinth organ, the folded chambers above its gills that let it breathe air, also makes the air bubbles for the male's nest. "Hide and Seek" is built from one source the same way: Imogen Heap's own voice, run through a harmoniser, is the whole arrangement. ## Biological Superpowers & Stats - **Taxonomy**: *Betta splendens* - **Danger Level**: Low - **Conservation Status**: Vulnerable ([IUCN Red List](https://doi.org/10.2305/iucn.uk.2011-1.rlts.t180889a7653828.en)) - **Superpower**: Breathes air through a labyrinth organ above its gills - **Habitat**: Typically shallow ponds, rice paddy fields and puddles in Southeast Asia - **Diet**: Mosquito larvae and other water insects - **Tags**: fish, freshwater, insectivore, domestic-pet, colorful ## Natural History & Behavior ## Air-breathing in a puddle The Siamese fighting fish (*Betta splendens*) can breathe air. It belongs to the labyrinth fishes, named for the labyrinth organ: folded, bony structures in paired chambers above the gills that let the fish take in air. Life in hypoxic (low-oxygen) water appears to have driven the diversification of this group. The wild betta is typically found in standing water, from shallow ponds and rice paddy fields to puddles. In one wild population in Thailand the water averaged 29.9°C and about 5.0 cm deep, and its dissolved oxygen averaged about 3.8 mg/L, swinging between 0.0 and about 7.4 mg/L. ## Small, short-lived and hungry FishBase gives a maximum length of 6.5 cm, and the USGS lists the size as 6 cm. The maximum reported age is 2 years. The species is native to Southeast Asia, including the northern Malay Peninsula, central and eastern Thailand, Cambodia and southern Vietnam. Bettas are carnivores that eat mosquito larvae and other water insects. One estimate says an adult male eats about ten to fifteen thousand larvae per year. The IUCN Red List rates the species Vulnerable, in an assessment published in 2011. ## Fins up, gills out When a male meets another male, he spreads his fins and flares out his gill covers almost immediately. As the fight goes on, the fish bite each other, particularly on the fins and flanks. Male bettas are among the most aggressive of the labyrinth fishes. Fights between two males were popular in Thailand for gambling, and the first fish to retreat was deemed the loser. The modern aquarium betta is a product of almost 100 years of selective breeding, first for aggression and now for bright colors and elaborate fins. The wild betta, by comparison, is dull brown or green. ## Dad builds the nursery > **The bubble nest** > A bubble nest allows eggs to develop in water with elevated temperature, low pH and low dissolved oxygen, relatively free of predators. Placing the eggs at the surface increases oxygen exchange, and the nest also keeps them from drying. In breeding tanks, the male wraps his body around the female and fertilizes the eggs as she releases them. Then he picks the eggs up in his mouth as they fall and places them in the bubble nest. About 300 eggs are released per spawning event. The male adds bubbles to the nest when needed and keeps newly hatched larvae in it. ## Frequently Asked Questions ### How big does a Siamese fighting fish get, and how long does it live? FishBase lists a maximum length of 6.5 cm for males or unsexed fish, and a maximum reported age of 2 years. AnAge also gives 2 years as the maximum longevity. *(Source: [FishBase]())* ### Why does a betta build a nest out of bubbles? The wild bettas the University of Florida describes in Thailand lived in shallow water that was hot, acidic and short of oxygen. A floating nest of bubbles lets the eggs develop there with fewer predators around, gives them better oxygen exchange at the surface and keeps them from drying out. *(Source: [UF/IFAS Extension, University of Florida]())* ### Do wild bettas look like the ones in pet shops? No. The University of Florida describes the wild betta as dull brown or green. The bold colors and long fins of pet bettas came from selective breeding in captivity. *(Source: [UF/IFAS Extension, University of Florida]())* ## Sources 1. [Evolution, Culture, and Care for Betta splendens. UF/IFAS Extension, University of Florida.]() 2. [Betta splendens, Siamese fighting fish. FishBase.]() 3. [AnAge entry for Betta splendens. AnAge: The Animal Ageing and Longevity Database.]() 4. [Betta splendens Regan, 1910. USGS Nonindigenous Aquatic Species database.]() 5. [Siamese Fighting Fish (Betta splendens) Ecological Risk Screening Summary. U.S. Fish and Wildlife Service.]() 6. [Vidthayanon (2011). Betta splendens. The IUCN Red List of Threatened Species 2011: e.T180889A7653828.]() 7. [Thongprajukaew et al. (2025). Recovery of Male Siamese Fighting Fish (Betta splendens) After Overland Shipping. Animals.]() *Published October 10, 2026. 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