大口抟鱼 · Brunei Beauty

Overview

Betta macrostoma is a large paternal mouthbrooder whose red males carry a distinct opercular patch and dorsal eyespot. Pair compatibility and undisturbed incubation are central challenges. A randomly selected male and female may not tolerate each other, and the weaker fish can be killed.

Distribution & habitat

It is known only from Brunei and the northern tip of Sarawak, with Malaysian records around the Baram district near Marudi. Shaded pools above rainforest waterfalls and quiet sections beside river channels provide habitat. Surrounding flow may be fast, but the fish occupy still areas over stones, gravel, and some leaves. Water is clear to slightly brown, acidic, and extremely low in minerals. Individual pools may hold a single adult, a pair, or several juveniles.

Aquarium setup

Create several shaded retreats with wood, roots, pots, or pipes. Leaves add cover and microorganisms. Use dim lighting, tolerant plants, floating cover, and gentle filtration. Secure the lid against jumps while retaining humid air above the surface. Its pool habitat does not imply a need for strong current in the aquarium.

Diet & feeding

Insects, small invertebrates, and zooplankton are likely prey; shrimp sharing its habitat may also be eaten, but this remains uncertain. Dry food is often learned. Supplement with live or frozen water fleas, brine shrimp, and bloodworms, with occasional earthworms for larger fish. Avoid overfeeding.

Behaviour & compatibility

A compatible pair is preferable to a community. Temporary group housing may allow natural pair formation, but males often fight continually and females also establish dominance through disputes. Established pairs usually coexist peacefully when space is sufficient. Do not leave randomly paired fish to endure sustained aggression.

Sexual dimorphism

Males tend to be larger and more colorful, with broader heads and longer fins. Red coloration and the dorsal eyespot are characteristic male features.

Breeding

Courtship includes gaping and fin spreading before repeated embraces release small egg batches. Both adults may collect eggs; those gathered by the female are transferred into the male's mouth. Brooding males need exceptional quiet because disturbance increases the chance of swallowing the brood.

Leaving the female avoids disruptive removal, but in smaller aquariums she may harass him or consume fry, requiring separation. Reported incubation spans roughly fourteen to thirty-five days. Fry have been raised separately, with the male, or with both parents. They take microworms and brine shrimp nauplii immediately. Feed small varied portions several times daily because excessive food readily causes intestinal problems. Daily modest water changes limit organic waste, while tight cover maintains moist warm air.

Notes

Keep locality populations separate when maintaining bloodlines. Its narrow natural range makes reliable provenance and breeding records especially valuable.