Flying Fox
Epalzeorhynchos kalopterum
Cyprinidae
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About
The flying fox is bought by mistake more often than on purpose: it is the fish people take home believing it is a Siamese algae eater. It is not, and the two differ in ways you can see across a shop tank. The flying fox carries a gold stripe running immediately above its brownish-black lateral line, and its dorsal, anal and ventral fins are transparent at the front with a thick black band along the edge — Seriously Fish adds red and white edging as the simplest field mark. Our Siamese algae eater has a single black stripe with nothing above it and plain, unmarked fins. Do not try to separate them on barbels: Seriously Fish credits two pairs to the flying fox AND two pairs to Crossocheilus langei, the fish usually sold as the SAE, so the barbel count that hobby guides lean on proves nothing. The difference that matters is what they do. The SAE genuinely eats black brush algae; of the flying fox, Seriously Fish says it "does not do so with the same efficacy as some Crossocheilus species" and that "there's little worth in purchasing it with that purpose in mind", and Maidenhead Aquatics says flatly that it should not be considered an algae eater. What you have instead is a 16 cm labeonine cyprinid from the same genus as our red-tail shark and rainbow shark, and it grows into the same temper: territorial with age, murderous toward anything shaped like itself, and best kept one to a tank in the majority of cases, with a territory a metre across.
Care
One fish, 120 cm of length, 200 litres or more, sand or very fine rounded gravel, cobbles and bogwood arranged to break every sight line. Seriously Fish gives 120 x 45 cm as the smallest base and a territory of at least a metre in diameter per individual; Maidenhead allows singly or in a group of five or more, but never two or three, because in small numbers one fish takes all of it. Keep Crossocheilus, Garra, Gyrinocheilus and other Epalzeorhynchos out entirely — Seriously Fish reports those are attacked constantly — and avoid slow, laterally compressed fish such as discus and angelfish. Loaches from Chromobotia, Botia, Syncrossus and Yasuhikotakia are generally left alone. Water 24-26 C, pH near neutral, soft to moderately hard, well oxygenated with moderate flow and no accumulated waste. The lid must be tight with no gaps around equipment: this fish is an expert jumper. Add it last, so it does not claim the whole tank before anything else arrives.
Diet
Grazes aufwuchs — algae plus the small crustaceans and insect larvae living in it — but it will not clear a tank of algae. Vegetable-rich dried foods, sinking wafers, peas, courgette, cucumber and spinach, with small live or frozen foods a few times a week.
Tankmate compatibility
Gets along with (165)
Possible with care (210)
Avoid (43)
Computed by the AquaSage engine for a spacious reference tank — always check the full verdict for your exact setup in the calculator.
Telling males from females
What works for this species, most reliable first.
- Colour and patternA hint only · from about 6 months, and only on a settled fish
In rainbowfish, killifish and several barbs the male carries the colour — deeper and more saturated, intensifying further when he displays.
- Extended finsA hint only · from about 8 months, and later in a suppressed male
On many cichlids and killifish the male's dorsal and anal fins draw out into trailing points as he matures, while the female's stay rounded.
- Belly depthA hint only · only on well-fed adults, and only as a comparison
For most tetras, barbs and rasboras this is all there is: a conditioned female is deeper through the belly than a male of the same length.
Also in these lists
Similar species
Same category and the closest water parameters — if this species isn't quite it, start here.
Sold in Lithuania
These Lithuanian shops listed this species in their public catalogue (checked August 8, 2026). Stock moves — ask before you travel.
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Frequently asked questions
- What tank size does a Flying Fox need?
- A Flying Fox needs an aquarium of at least 200 litres (52.8 US gallons) with a footprint at least 120 cm (47.2 in) long — for this species, swimming length matters as much as raw volume.
- What water parameters does a Flying Fox need?
- Flying Fox does best at 20–27 °C (68–80.6 °F), pH 6–7.5 and a general hardness of 2–12 °dGH.
- Is the Flying Fox suitable for beginners?
- Flying Fox sits in the middle of the difficulty scale — manageable for a careful beginner who has done the reading, but it has specific needs worth researching first.