红搏鱼

Overview

An evenly deep-red body without a central flank blotch characterizes Betta rutilans. Pale filamentous pelvic-fin tips add contrast. This small bubble nester requires shaded, very soft acidic conditions, with the male performing nest care after spawning.

Distribution & habitat

It occurs near Anjungan in West Kalimantan, Indonesian Borneo, at sites associated with the Mempawah and Kepayang rivers. Peat-swamp forest and blackwater streams provide dense shade, negligible minerals, and a bottom covered by leaves, branches, and roots. Seasonal drying can leave fish surviving within damp litter for weeks.

Aquarium setup

Provide a footprint of at least about 45 × 30 cm. Roots, branches, tubes, and pots create retreats. Dried leaves support microorganisms useful as supplementary fry food, without a need for natural peat. Shade-tolerant and floating plants suit subdued lighting.

Maintain acidic water with very low general hardness and negligible carbonate hardness, using reverse-osmosis water if needed. Gentle filtration is sufficient. A secure lid prevents jumping while humid air remains available above the surface.

Diet & feeding

Insects and other small invertebrates are likely wild prey. Captive fish generally learn to accept dry foods, with regular live or frozen Daphnia, Artemia, and bloodworms adding variety. Avoid overfeeding.

Behaviour & compatibility

Large or active fish can intimidate it and dominate feeding, making an ordinary community unsuitable. Dedicated keeping or exceptionally peaceful, compatible companions is preferable.

Accounts of several pairs or one-male groups vary: some involve only brief disputes, while others show persistent aggression by dominant fish. A pair is more straightforward to manage; larger groups need close attention to actual compatibility.

Sexual dimorphism

Females develop slightly rounder bellies and somewhat duller color. Adult males have marginally longer pelvic, dorsal, and anal fins.

Breeding

Give the female abundant retreats. Without prior separation, the male can build in a tube or container, under a broad leaf, or among surface plants. He generally excludes her until the nest is complete. A receptive female becomes pale with dark flank bars. Repeated embraces release eggs that she catches with her pelvic fins before the male places them in the nest; she also retrieves loose eggs.

Broods usually contain fewer than 20 eggs, although around 50 is possible. Both adults can generally remain, but the female ceases active care while the male guards the nest and retrieves fallen larvae. Hatching takes about 24–48 hours, followed by another 3–4 days of yolk absorption in the nest. He loses interest after free swimming, and adults usually spare the offspring.

A close-fitting cover retains warm, humid air for labyrinth development. Offer microworms and Artemia nauplii in small, varied meals two or three times daily, avoiding excessive Artemia use. Make regular small water changes.

Notes

Before description it was traded as Betta sp. “Anjungan.” Similar red bettas can be difficult to distinguish because patterning varies; flank markings and fin characters are more useful together than redness alone.