Epalzeorhynchos kalopterum · Flying Fox

Overview

White-edged red-and-black fins and two pairs of barbels help identify Epalzeorhynchos kalopterum, commonly traded as Flying Fox. Territorial behavior intensifies with age, and individuals can exceed 15 years. Juvenile size and an algae-eater label conceal a substantial long-term commitment.

Distribution & habitat

Records mainly concern southern Thailand, the Malay Peninsula, and Borneo, Sumatra, and Java. Banjarmasin on Borneo is the type locality; associated drainages include the Kahayan, Barito, and Kapuas. Sumatran records include the Indragiri, Batang Hari, and Musi.

Fish graze sandy and rocky river or stream bottoms and enter flooded forest or floodplains seasonally. Development may disrupt these movements. Declines or losses among historical populations leave the precise range uncertain.

Aquarium setup

Cover matters more than a rigid decorative formula, although a river layout is well suited. Use gravel, smooth rocks, roots, and attached ferns or Anubias. Bright illumination encourages surface algae, while soft-leaved plants generally remain intact.

High oxygen availability, moderate circulation, and clean stable water are important because organic waste is poorly tolerated. Multiple specimens need far more room than minimum single-fish accommodation; extra hiding places alone do not create adequate territories.

Diet & feeding

Grazing supplies algae together with small crustaceans, insect larvae, and other surface organisms. Offer regular small live or frozen bloodworms, water fleas, and Artemia, plus good flakes, granules, and vegetable foods.

Shelled peas, cucumber, softened zucchini, spinach, and chopped fruit provide variety. Settled fish feed in midwater as well as browse growth on stones. Algae removal should not be mistaken for a complete feeding plan.

Behaviour & compatibility

Juveniles often hide, but adults can persistently harass similarly shaped fishes, especially close relatives and comparable algae grazers. Individual behavior varies, so isolated peaceful examples cannot guarantee a successful pairing.

Most other bottom dwellers, including cichlids and catfishes, are best avoided. Some loaches have coexisted successfully, but those loaches are not automatically compatible with one another. Robust active schooling fishes higher in the water are better candidates. Add this species last to reduce prior ownership of the whole aquarium.

One specimen is appropriate in most cases. Cohabitation should be attempted only in exceptionally spacious, well-sheltered aquariums, with each fish expected to require a territory approximately 1 m across. Continue monitoring subordinate fish.

Sexual dimorphism

Mature females are markedly fuller-bodied. Juveniles cannot be sexed dependably by appearance.

Breeding

Commercial production uses hormonal assistance, but a practical method for ordinary private aquariums is not established.

Notes

The older spelling kalopterus was corrected to kalopterum in 2013 to agree grammatically with the genus. Although it grazes algae, it should not be bought on the assumption that it performs like a specialized algae-control fish.

False flying fox and Siamese flying fox labels are applied to fishes from several genera. The white-edged colored fins and paired sets of barbels are more useful clues than a black stripe or algae-grazing behavior alone.