Flying Fox Care Guide - Aquarium Setup, Diet & Breeding

The Flying Fox, Epalzeorhynchos kalopterus, is a sleek, active cyprinid recognised by its dark horizontal stripe, bright gold edging and reddish or orange markings in the fins. Its streamlined body and downturned mouth reflect a life spent grazing across surfaces and exploring the bottom of the aquarium.

Although often sold as an algae eater, this species is more accurately an opportunistic omnivore. It investigates plants, wood, rocks and the substrate for algae, aufwuchs, small invertebrates and other edible material, but it does not remain exclusively focused on algae as it matures.

In the wild, Flying Foxes occupy clear, oxygen-rich waters with current, where seasonal changes in flow expose fresh feeding surfaces. They are agile swimmers and use their mouths to rasp and pick at growth on submerged rocks and other structures.

Young specimens are generally peaceful and useful members of a community aquarium, while adults can become assertive and territorial. Individual temperament varies, but mature fish often defend preferred feeding areas against similar-looking bottom-dwelling species.

The Flying Fox is native to mainland Southeast Asia, including parts of Thailand, Malaysia, Indonesia and the island of Borneo. It inhabits flowing freshwater streams and rivers, particularly areas with rocky or sandy bottoms and plentiful plant and algae growth.

A single adult Flying Fox should be provided with an aquarium of at least 200 litres, ideally measuring around 120 cm long by 45 cm wide or larger. Use efficient filtration and good water movement while leaving calmer areas for resting. A fine gravel or sand substrate, smooth stones, driftwood, sturdy plants and plenty of shaded retreats create a natural layout, while open swimming space along the front and middle of the tank allows this active fish to move freely. Secure the lid, as startled individuals can jump.

Up to 15 cm (6 in) in length. Females are often slightly deeper-bodied and heavier than males, while males tend to remain slimmer; overall size differences are modest.

Offer a varied omnivorous diet consisting of quality sinking pellets or wafers, algae-based foods, blanched vegetables such as courgette and spinach, and occasional frozen or live foods including bloodworm, brine shrimp and daphnia. They should not be expected to survive on naturally occurring algae alone, particularly in a mature aquarium where their nutritional needs exceed the available growth. Feed modest portions and remove uneaten vegetables before they decay.

Flying Foxes can live with peaceful to moderately robust community fish such as larger tetras, rasboras, danios, peaceful barbs, rainbowfish, gouramis and appropriately sized corydoras. Avoid housing them with highly aggressive cichlids, fin-nipping species or slow fish that cannot compete for food. They may quarrel with other Flying Foxes and are especially prone to territorial disputes with Red-Tailed Black Sharks, Rainbow Sharks, Chinese Algae Eaters and similar algae-eating cyprinids, so these combinations are best avoided or attempted only in a very large, carefully structured aquarium.

Flying Foxes are rarely bred in home aquariums. Sexually mature fish may spawn in very large, mature setups, but successful breeding generally depends on carefully controlled conditions and is more commonly achieved on commercial farms with hormonal assistance. There is no dependable, simple breeding method for the average aquarist, and any eggs or fry are unlikely to survive alongside adult fish without a dedicated breeding system.

Females are usually fuller through the abdomen and may appear broader when mature, whereas males are generally more slender and streamlined. These differences can be subtle, especially in young or poorly conditioned fish.