fish · Cyprinidae
Flying fox
Epalzeorhynchos kalopterus
Wild range: Southeast Asia — southern Thailand (Surat Thani, Yala), Peninsular Malaysia, and the Greater Sunda Islands of Sumatra (Indragiri, Batang Hari, Musi), Borneo (Kapuas, Kahayan, Barito basins), and Java. Type locality Bandjarmasin, South Kalimantan, Borneo. Wild populations reportedly declining; trade fish are farm-bred. (Asia)
At a glance: Flying fox care
Compiled reference information. Review the care notes and original sources below.
What temperature is listed for Flying fox?
The compiled profile lists 20.0–26.0 °C for Flying fox (Epalzeorhynchos kalopterus). Check the original sources below for context and differing recommendations.
What tank size is listed for Flying fox?
The profile lists a minimum tank volume of 55.0 US gallons (208.0 liters). Volume alone does not establish suitability; consider dimensions, group size and other inhabitants alongside the full care notes.
What pH is listed for Flying fox?
The compiled profile lists a pH of 6.0–7.5. Review the cited care sources alongside the other water parameters in this profile.
Natural habitat
A slender labeonine cyprinid of moderately flowing, well-oxygenated streams and rivers in southern Thailand, Peninsular Malaysia, Sumatra, Borneo, and Java, where it grazes aufwuchs from sandy and rocky substrates and is often seen under floating objects such as boats and floating houses (Seriously Fish; FishBase; Maidenhead Aquatics). Identified by a bold black lateral stripe edged above in gold, red-to-black fins with white edges, and two pairs of barbels. Sold young at 2.5–5 cm but grows to about 14–16 cm and can live well over a decade.
Where they are found
Catalog primary kept as the established trade/ITIS spelling Epalzeorhynchos kalopterus (ITIS TSN 639590 'Epalzeorhynchos kalopterus (Bleeker, 1851)'; GBIF accepted 'Epalzeorhynchos kalopterus (Bleeker, 1850)'; Maidenhead Aquatics/Fish Laboratory/Wikipedia use kalopterus). Catalog of Fishes and FishBase now spell it Epalzeorhynchos kalopterum (Bleeker 1850) following Kottelat (2013), who treated Epalzeorhynchos as neuter (Roberts 1989) — kalopterum is in aliases; Seriously Fish and Aquatic Arts also use kalopterum. Original combination Barbus kalopterus Bleeker 1850 (Natuurkundig Tijdschrift voor Nederlandsch Indië 1:13; holotype RMNH 12784; type locality Bandjarmasin, Borneo). Later spelled kallopterus by Bleeker; Epalzeorhynchus callopterus Günther 1868 is an unjustified emendation (CoF). Authorship year 1850 per CoF, FishBase, GBIF and Seriously Fish; ITIS gives 1851 (noted, not adopted). Family Cyprinidae, subfamily Labeoninae (CoF/FishBase). IUCN Red List Least Concern (assessed 2019; FishBase Version 2025-2; CoF). LOOKALIKE CAUTION: 'Siamese flying fox' / 'false flying fox' trade names are applied to Crossocheilus spp. (Siamese algae eater, C. oblongus/langei/siamensis), Garra cambodgiensis, and sometimes Gyrinocheilus aymonieri; the true flying fox differs by red/black white-edged fins, a gold line above the black stripe, and two pairs of barbels (Seriously Fish; Maidenhead Aquatics). See catalog siamese-algae-eater, true-siamese-algae-eater, and chinese-algae-eater.
Aquarium care
Locked minimum 55 US gallons (~208 L) for one adult: Fish Laboratory 55 gal; Aquatic Arts 50 gal for a single adult and 120+ gal for a group; Seriously Fish and Maidenhead Aquatics ask for at least a 120 cm (4 ft) long tank, SF preferring a 120 × 45 cm footprint (~64 US gal); FishBase cites minimum 100 cm. Locked 20–26°C, pH 6.0–7.5, GH 2–12 dGH (Seriously Fish and Aquatic Arts agree on temp and pH; Maidenhead pH 6.2–7.0, dH up to 12, 24–26°C; FishBase 24–26°C, pH 6.5–7.0); avoid long-term keeping at the top of the tropical range (Aquatic Arts). A river-style layout of sand or fine rounded gravel, smooth cobbles, boulders and driftwood with epiphytes (Anubias, Java fern, Bolbitis), bright light for biofilm, moderate current, high dissolved oxygen, and frequent water changes — it is intolerant of organic waste build-up (Seriously Fish; Maidenhead Aquatics; Aquatic Arts). Use a tight lid: it is an expert jumper (Maidenhead Aquatics; Aquatic Arts). Add it to the tank last so it does not claim the whole space (Seriously Fish).
Feeding
Omnivorous aufwuchs grazer: in the wild it eats algae, biofilm, worms, small crustaceans, and insect larvae (FishBase; Seriously Fish). Offer quality sinking pellets, granules, flakes, and algae wafers plus regular frozen or live bloodworm, Daphnia, Artemia, and Mysis, and fresh vegetables such as blanched zucchini, cucumber, peas, and spinach (Seriously Fish; Maidenhead Aquatics; Aquatic Arts). It browses green algae and biofilm but is a much weaker algae-control fish than Crossocheilus and should not be bought as an algae eater (Seriously Fish; Maidenhead Aquatics).
Compatibility
Peaceful toward dissimilar fish when young, but it becomes more territorial with age and is especially aggressive toward its own kind and similar-looking fish: other Epalzeorhynchos (rainbow shark, red-tail shark), Crossocheilus (Siamese algae eaters), Garra, and Gyrinocheilus are often attacked constantly (Seriously Fish; Maidenhead Aquatics; Aquatic Arts). Keep one per tank. A group is only an option in a very large, heavily broken-up tank with 5–6 or more fish (Maidenhead Aquatics; Aquatic Arts); SF suggests each fish needs about a 1 m territory. Good tankmates are robust, active schooling cyprinids (danios, Devario, larger rasboras and barbs) and botiid loaches; avoid most bottom-dwelling cichlids and catfish, which may be harassed, and slow, deep-bodied fish such as angelfish or discus (Seriously Fish; Maidenhead Aquatics). Will eat dwarf shrimp; larger shrimp and snails are usually ignored (Aquatic Arts). Community_safe false. Do not confuse with the 'Siamese flying fox' or 'false flying fox' (Crossocheilus/Garra/Gyrinocheilus) sold under similar names.
Breeding
Not known to have been bred in home aquaria (Seriously Fish; Maidenhead Aquatics); trade fish are farm-bred with hormones. Fish Laboratory also rates captive breeding difficult. Females are fuller-bodied when mature.
Sources
Compiled from multiple independent care sheets — not copied from a single site.