Betta mandor Care Guide - Habitat, Diet & Breeding

Betta mandor is a relatively small wild betta with a slender body, rounded fins and the characteristic upturned mouth of a surface-feeding labyrinth fish. Its subdued brown, red and iridescent tones can become much more noticeable when the fish is displaying, particularly in mature males. Individual colour varies with mood, sex and lighting.

This species is a mouthbrooding betta rather than a bubble-nest builder. The male carries the developing eggs in his mouth, a fascinating adaptation that allows the fish to reproduce in habitats where floating vegetation and stable nesting surfaces may be scarce.

In the aquarium, Betta mandor is generally more secretive and less continuously active than many domestic bettas. It spends time exploring shaded areas and may display boldly toward rivals or a potential mate, but it does not form a coordinated shoal. Males can be territorial, especially in a confined space.

In nature, it inhabits quiet forest waters and peat swamps coloured darkly by decomposing leaves and wood. These environments are typically low in mineral content, dimly lit and rich in submerged roots and leaf litter, creating a natural setting where cover is as important as open swimming space.

Betta mandor comes from peat-swamp and blackwater habitats around Mandor in West Kalimantan, on the Indonesian part of the island of Borneo. It is associated with the wider western Bornean freshwater region and its tannin-rich, highly acidic waters.

A single Betta mandor should have at least 60 litres, with a footprint of approximately 60 × 30 cm or larger; a pair or community group needs more floor space and visual barriers. Use gentle filtration with subdued flow, a secure lid and warm, soft, tannin-rich water. Dark sand or fine, smooth substrate, leaf litter, driftwood, roots, dense plants and floating cover help recreate its peat-swamp habitat. Leave some quiet open water, but provide several shaded retreats so fish can avoid one another.

Up to about 7 cm (2.8 in) in total length. Males may reach a slightly greater length and have more extended fins than females.

Betta mandor is a carnivorous micropredator. Offer a varied diet of small live or frozen foods such as mosquito larvae, daphnia, brine shrimp, blackworms and finely chopped bloodworm, supplemented with a good-quality soft betta or carnivorous micro-pellet where accepted. Small, regular meals are preferable to large portions, and live foods are particularly useful when conditioning adults for breeding.

Betta mandor is best kept alone, as a compatible pair, or in a carefully planned species aquarium. Suitable companions for a sufficiently spacious blackwater community may include small Boraras rasboras, peaceful diminutive rasboras and other calm species that tolerate soft, acidic water. Avoid fin-nipping fish, boisterous tankmates, large predators and other male bettas. Even peaceful community fish can outcompete this shy species for food, so a species-only setup is often the safest choice.

Betta mandor is a paternal mouthbrooder. Condition a compatible pair with varied live and frozen foods, then introduce them into a quiet, dimly lit breeding aquarium with soft, acidic water and plenty of cover. After spawning, the male gathers the eggs and incubates them in his mouth, usually for around 10 to 14 days. Once the fry are released, offer very small live foods such as infusoria and newly hatched brine shrimp, and remove the female if the pair becomes aggressive.

Males are usually more colourful, slimmer and longer-finned, with stronger iridescent or reddish markings during display. Females are generally shorter-bodied and fuller through the abdomen, with shorter fins and less intense colouration.