Brunei Beauty
Betta macrostoma, known internationally as the Brunei Beauty, is a rare wild betta found only in Brunei and the northernmost part of Sarawak on the island of Borneo. Males display a striking orange-red body with black-edged fins and eye-like markings (ocelli) that give them a refined, distinctive appearance. One of the species' most fascinating traits is mouthbrooding: after spawning, the male carries and protects the eggs in his mouth until they hatch. Because this species thrives in cool, strongly acidic soft water, it requires careful water quality management and is best suited to experienced keepers, with adults typically reaching about 7 to 10 cm in length.
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Apply as a breederBrunei Beauty key facts
- Care level
- Advanced
- Lifespan
- 2-4 years
- Size
- About 7-10cm
- Temperature
- 20〜25℃
- Diet
- Frozen and live foods (Daphnia, Artemia, bloodworm), dried foods
- Tank
- From about 80 x 30cm (72 litres) for a pair. Provide shaded cover with wood and leaf litter, and close the lid completely against jumping.
- Water Temperature & Quality
- Keep it cool at 20-25C with pH 4.0-6.0 and 0-5 dGH - strongly acidic and very soft. Warm water quickly puts the fish out of condition.
- Tank Mates
- Not a community fish; keep as a pair. A group is sometimes maintained temporarily so fish can choose partners, but males fight hard.
- Diet & Feeding
- It eats insects and small invertebrates in the wild. Offer Daphnia, Artemia or bloodworm regularly alongside dried foods.
- Breeding & Spawning
- A paternal mouthbrooder. The male wraps around the female at spawning and incubates for 14-35 days, releasing fry of 5mm or larger.
- Health & Notes
- Listed as Vulnerable by the IUCN. Its range is tiny and supply is limited, so check the provenance of any fish, and secure a location that stays cool.
About Brunei Beauty
Betta macrostoma (Brunei Beauty) is a rare wild betta endemic to Borneo, known for its orange-red coloring and mouthbrooding behavior, best suited to experienced keepers.
7 things to know before welcoming a Brunei Beauty
1Water Quality Is Key
This species prefers cool, strongly acidic soft water, so it can struggle in conditions suited to typical tropical fish. Set up equipment to precisely control pH and temperature before bringing one home.
2Suited to Experienced Keepers
This species is considered advanced-level to keep. Beyond precise water quality and temperature control, its territorial nature requires careful handling, so prior tropical fish experience is recommended.
3Males Guard the Eggs
After spawning, the male incubates and protects the eggs in his mouth in a behavior known as mouthbrooding. He continues caring for them until the fry can swim freely, so attempting to breed this species requires patient, sustained observation.
4Tank Size for Adults
Adults grow to about 7 to 10 cm. Plan for a tank spacious enough to include hiding spots and shaded areas, whether keeping a single fish or a pair.
5Coloring and Individual Variation
Males have an orange-red body with black-edged fins and eye-like markings, though the intensity of color and pattern varies between individuals. Females tend to have more subdued coloring than males.
6Best Kept Alone
This species is highly territorial, so caution is needed both between males of the same species and with other tankmates. It favors a calm environment, making solo keeping or a carefully matched pair the standard approach.
7Prepare the Environment First
In the wild, this species lives in cool, acidic waters, so it's important to set up filtration, temperature control, and pH adjustment before bringing one home. Introducing it without a properly prepared environment can put unnecessary stress on the fish.
Frequently asked questions about Brunei Beauty
- Q.Can beginners keep this species?
- A.Betta macrostoma is considered an advanced-level species. Since it requires stable management of cool, strongly acidic soft water, it's best attempted after gaining experience with tropical fish keeping.
- Q.How large does it grow?
- A.Adults grow to about 7 to 10 cm, somewhat larger than typical ornamental betta varieties.
- Q.Is this species subject to CITES?
- A.No, Betta macrostoma is not subject to CITES.
- Q.Can it be kept with other fish?
- A.Because this species is highly territorial, mixing it with other fish requires caution. Solo keeping, or a carefully matched pair, tends to work best.
- Q.Is breeding difficult?
- A.This species has a distinctive mouthbrooding behavior, where the male incubates the eggs in his mouth. Breeding requires solid experience, since it involves both water quality management and close observation of the male's condition.
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