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Brunei Beauty

Betta macrostoma

Freshwater South-east Asia

A legendary wild mouthbrooding betta exhibiting fiery orange-red sides, an ornate caudal pattern, and an immense mouth. Highly demanding in captivity, it requires cool, extremely pristine, acidic water. They are master escape artists capable of squeezing through minute gaps, mandating a tightly sealed aquarium lid.

Also called: Brunei beauty, Orangecheek betta, Peacock betta, Spotfin betta.

9 cm adult length, drawn to scale. torpedo body.

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

What it needs

ItemValueBecause
Adult length 9 cm Used for the Space check: the tank must be long enough for the fish to turn round.
Smallest tank 100 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 20 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 20 to 24 C Stock sharing a tank need overlapping ranges.
pH 4.5 to 6.5 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 All levels Fish that use different levels share a tank more easily.
Lifespan About 5 years A fish is a long commitment.
Experience Experienced keepers only 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

Brunei Beauty is an carnivore that swims in all levels of the tank. 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.