Parosphromenus opallios

Overview

Parosphromenus opallios is a small peat-swamp gourami from Central Kalimantan, formerly circulated under a Sukamara label. Red, black, and blue male fin patterns help identification, whereas females are difficult to distinguish from relatives by appearance alone.

Distribution & habitat

It is native to Indonesian Borneo's Central Kalimantan, with records around Sukamara, Pangkalan Bun, and the Benipah system farther east. The complete range remains incompletely resolved.

Peat forests and connected black-water streams provide shade, very low mineral content, and acidity. A Sukamara pool shared with Parosphromenus linkei had extensive surrounding vegetation cleared for agriculture. Natural coexistence does not make aquarium mixing appropriate for preserving stock identity.

Aquarium setup

Allow about 40 × 20 cm for a pair. Wood, roots, leaves, pots, and pipes create shade and caves; a bare bottom is another option. Subdued lighting, shade-tolerant plants, and floating cover suit the fish. Leaf-associated microbes provide supplemental fry food.

Extremely soft acidic water with negligible carbonate hardness may require reverse osmosis. Only use a biologically mature aquarium. Gentle sponge filtration and weekly changes of about 5–10% avoid disruptive fluctuations. Filterless maintenance is limited to lightly stocked pairs with controlled feeding and rigorous upkeep.

Diet & feeding

It mainly hunts tiny aquatic invertebrates and needs varied small live foods, including brine shrimp nauplii, Daphnia, Moina, mosquito larvae, and microworms. Most dry foods are refused. Occasional acceptance of frozen food does not remove the need to prepare appropriate live foods.

Behaviour & compatibility

A species pair is preferable for observation and rearing. Mixed-sex groups are possible, but other adults normally reduce fry survival. Do not mix related species because females are difficult to identify and hybrids are possible. Busy communities with forceful feeding competitors are unsuitable.

Sexual dimorphism

Male fins have black near-edge bands, thin blue-green outer margins, and inner blue iridescence. The inner blue tail band is particularly narrow, beside a black-to-red central area. Pelvic fins and filaments are blue, with a dark terminal blotch.

Females lack bright bands, have a rounder rear dorsal edge, and become pale yellow near spawning. Both sexes can show a dark oblique eye mark and rapid mood-related changes.

Breeding

The male courts head-down around a small cave territory. Temporary pairs attach eggs overhead after spawning embraces. Some males add a few bubbles, others do not. Inexperienced fish can drop or eat eggs.

The female guards outside and the male tends the brood. Hatching occurs in about 24–36 hours, mobility another four to six days later, and complete departure after a further three to five days. Initial Paramecium or rotifers soon give way to brine shrimp nauplii. Complex mature aquariums may retain offspring beside parents; simpler ones favor separate rearing.

Notes

Sukamara is a historical locality label, not proof that every fish from that area is this species. Assess the full male pattern with trustworthy provenance.