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Slender Betta

Betta bellica

Freshwater South-east Asia

A large, bubble-nesting wild betta featuring an elongated body shimmering with greenish iridescence. Originating from tea-coloured peat bogs, it demands warm, soft, acidic water rich in tannins. An airtight lid is essential to maintain humid air for labyrinth breathing.

Also called: Slender betta, Slim betta, Striped betta.

9.5 cm adult length, drawn to scale. slim body.

Try it in the planner Opens a tank sized to its minimum with 1 fish added.

What it needs

ItemValueBecause
Adult length 9.5 cm Used for the Space check: the tank must be long enough for the fish to turn round.
Smallest tank 90 L, at least 80 cm long estimated The least water and floor length this species is kept in for good, as a single fish or smallest group.
Extra water per added fish 15 L estimated What each further fish adds once the minimum is met.
Waste load Class 2 of 5 estimated How much waste an adult makes against its size. Feeds the Load check.
Temperature 24 to 29 C Stock sharing a tank need overlapping ranges.
pH 4.5 to 6.8 Compared with tankmates in the Water check.
Hardness GH 1 to 6, KH 0 to 3 Degrees of general and carbonate hardness.
Flow Low Low-flow fish are stressed in a strong current.
Light Dim Matched to the lighting class on the needs sheet.
Group size Single fish is fine Not a schooling species.
Temperament Peaceful Territorial: weak.
Swims in Upper water Fish that use different levels share a tank more easily.
Lifespan About 4 years A fish is a long commitment.
Experience Some experience helps A guide to how forgiving the species is of mistakes.
Jumps Yes Keep the tank covered.

Tags marked estimated are judged from the size and habits of the species rather than measured, so treat them as a sensible default.

Diet and tank layout

Slender Betta is an carnivore that swims in the upper water. It is safe with plants. Give it plenty of cover. It will eat fish small enough to swallow.

Tankmates

Works with

Depends

Avoid

Compare any two fish on the compatibility page, or print the equipment for a stock on the needs sheet. How this is worked out: the method.