At a glance the quick version
Maximum standard length about 6 cm.
Looks how to spot one
Scales, slender labyrinth fish
A small, slim fighting-fish relative with a short-finned wild shape. Like other bettas it has a labyrinth organ that lets it gulp air from the surface. Males carry longer fins and stronger colour than females.123
Personality what they are like
A relatively gentle betta, as its scientific name suggests. Males can still spar over territory and get more assertive when breeding, but with plenty of cover several can share a tank.23
Daily activity how busy a day looks
Calm, slow swimmer that likes still water and spends time near plants and the surface.23
Grooming and care the hands-on bits
Keep a tight-fitting lid because it can jump. Leave a layer of humid air above the water so it can breathe at the surface comfortably, and keep the water clean and still.31
Home where they are happiest
A tank of roughly 40 litres with a 45 x 30 cm footprint suits a pair. Temperature 20-28 C (FishBase gives 24-28 C), pH 5.0-7.5, soft to moderately hard water. Dense planting, floating plants, leaf litter and gentle filtration recreate its still, shaded habitat.213
Food basics what goes in the bowl
Feeds on small aquatic and land insects in the wild. Accepts dried foods, but regular small live or frozen foods such as daphnia, brine shrimp and bloodworm help bring out its colour.23
Company who they like around
Best kept as a pair or small group on its own or with very peaceful small fish; not a typical community-tank fish. Pairs can be moved to their own tank for breeding.23
The story where it all began
Described by Ladiges in 1975 from Southeast Asian lowland waters. It is a close wild cousin of the Siamese fighting fish and belongs to the same species complex. In Thailand it has long been line-bred, and it is also selectively bred for the ornamental fish trade.123
Fun facts for the dinner table
- 1
Its species name imbellis is Latin for peaceful, a nod to its gentler nature compared with other fighting fish.2
- 2
The male builds a nest of bubbles at the surface and looks after the eggs and fry on his own.2
- 3
Eggs hatch in one to two days, and the young swim freely three to four days after that.2
- 4
It can breathe air from the surface thanks to its labyrinth organ, so it copes well in still, low-oxygen pools.1
Recognised by the official bits
- IUCN Red List
- Least Concern (assessed 5 January 2019)1
- Taxonomy
- Family Osphronemidae; described by Ladiges in 1975; part of the Betta splendens species complex3
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Crescent Betta. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- Feedingevery day
- Temperature checkevery day
- Water changeAbout 25% of the waterevery week
- Water testevery week
- Filter rinseevery month
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Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at [email protected] and we will fix it.
- FishBase: Betta imbellis summary fishbase.seused for origin, size, water parameters, IUCN status, colour, breeding
- Seriously Fish: Betta imbellis seriouslyfish.comused for care, tank size, diet, behaviour, etymology, breeding
- Wikipedia: Betta imbellis en.wikipedia.orgused for other names, lifespan, distribution, behaviour
Checked 2026-09-30. Text is written in our own words from these sources.