Betta (Siamese Fighting Fish)
Betta splendens
Osphronemidae
About
Betta splendens, the Siamese fighting fish, is a labyrinth fish from the slow, shallow waters, rice paddies and floodplains of Thailand and neighbouring Southeast Asia. Centuries of selective breeding have produced spectacular finnage and colour in males, from veiltail to halfmoon and plakat forms. As an air-breather with an accessory labyrinth organ, it tolerates warm, still, low-oxygen water but is intolerant of cold and chilling drafts. Males are highly territorial and cannot be housed together; even females may squabble. A warm, well-lidded, gently filtered planted tank suits it best.
Care
Keep one male alone in a heated 20 L+ planted tank at 26-28°C with gentle flow and a tight lid. Feed a carnivorous diet; never house two males together.
Diet
Carnivore; betta pellets plus live/frozen bloodworm, daphnia and brine shrimp.
Tankmate compatibility
Gets along with (18)
Possible with care (196)
Avoid (57)
Computed by the AquaSage engine for a spacious reference tank — always check the full verdict for your exact setup in the calculator.
Full tank-mates guide with reasons →Telling males from females
What works for this species, most reliable first.
- Dorsal fin shapeStrong · from about 4 months
In most gouramis the dorsal fin ends differently between the sexes, and it can be read from outside the glass without touching the fish.
- The ovipositorStrong · from about 4 months
A small white tube at the vent, just behind the ventral fins, visible on a mature female from below or head-on. It reads as a single white dot.
- Extended finsA hint only · from about 8 months, and later in a suppressed male
On many cichlids and killifish the male's dorsal and anal fins draw out into trailing points as he matures, while the female's stay rounded.
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Frequently asked questions
- What tank size does a Betta (Siamese Fighting Fish) need?
- A Betta (Siamese Fighting Fish) needs an aquarium of at least 20 litres (5.3 US gallons) with a footprint at least 40 cm (15.7 in) long — for this species, swimming length matters as much as raw volume.
- What water parameters does a Betta (Siamese Fighting Fish) need?
- Betta (Siamese Fighting Fish) does best at 24–30 °C (75.2–86 °F), pH 6–8 and a general hardness of 5–20 °dGH.
- Is the Betta (Siamese Fighting Fish) suitable for beginners?
- Yes — Betta (Siamese Fighting Fish) is one of the easier species to keep and forgives typical first-tank mistakes, as long as the aquarium is cycled and maintained.