A slender, active cyprinid renowned as one of the few fish that reliably eats nuisance black beard and hair algae. Peaceful and hardy, identified by a single clean black stripe running through the tail fin.
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Mainland Southeast Asia, Thailand and the Malay Peninsula
Origin
Old World
Climate
🌴 Tropical
Water type
💧 Freshwater
Family
Cyprinidae
Genus
Crossocheilus
Part of the Algae eaters
Fish kept primarily as natural clean-up crew that graze algae, biofilm, and detritus off glass, plants, and hardscape. Effectiveness and adult size vary widely, so match the species to the tank.
More algae eaters coming soon.
Habitat & space requirements
From the minimum an animal needs to be kept humanely, up to the ideal setup. Bigger is almost always better — minimums are floors, not targets.
Photo coming soon
Minimum
Long active community
55 gal / 200 L (group of 4+)
Crossocheilus oblongus reaches 15 cm and is active, peaceful in groups but bullies solo. Group of 4+, 4-ft+ length, strong flow, and varied diet (sinks algae wafers + veg).
Photo coming soon
Recommended
Planted Asian community
75 gal / 280 L
Long footprint and a group of 5–6 in a planted tank with driftwood and flow. Pair with similarly active species (barbs, danios, larger rasboras).
Photo coming soon
Ideal
Asian river biotope
125 gal+ / 470 L+ biotope
Long planted biotope with strong flow, smooth rocks, and active group. Real algae control and natural patrol schooling behaviour.
Life & growth stages
How this animal changes through its life — each stage often has its own care, diet and space needs.
Photo coming soon
Egg
Fish eggs are small, translucent spheres, often laid in clutches on plants, substrate, or in a nest — or carried/brooded by a parent in livebearing and mouth-brooding species. A dark eye spot and the curled embryo become visible inside as development progresses.
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Fry
Newly hatched fry are tiny and semi-transparent, frequently still carrying a yolk sac that fuels them before they feed freely. They lack full fin structure and adult coloration, staying near cover until they can swim and forage on their own.
Photo coming soon
Juvenile
Juveniles look like miniature adults but with developing fins and muted or different markings; many species shift pattern and color as they mature. Growth is rapid at this stage given clean water and steady feeding.
Adult
Adults show the species' full size, finnage, and mature coloration, and are sexually mature. Many fish develop sex-specific differences in size, color, or fin shape, which can intensify during breeding.
Habitat & enclosure
Active and fast-swimming, so provide at least a 30-55 gallon tank with open swimming length. Keep at 75-80 F (24-27 C), pH 6.5-7.5, and soft to moderately hard water (5-15 dGH) with moderate flow. They appreciate planted setups with driftwood and moderate lighting.
They originate in flowing streams and flooded forests of mainland Southeast Asia and adapt well to typical community-tank conditions.
Substrate
Any substrate works; sand or fine gravel with driftwood and live plants suits them. Their natural habitat is rocky and root-strewn, so structure for grazing surfaces is welcome.
Equipment & setup
Standard community filtration with moderate flow and a heater is sufficient. A secure lid is important because they are accomplished jumpers, and moderate lighting supports plant and algae growth.
Diet
Omnivore with a strong appetite for algae, including stubborn black beard algae, when young. Round out the diet with algae wafers, sinking pellets, blanched vegetables, and occasional frozen foods. As they mature they eat more prepared food and graze less algae, so don't rely on them alone.
Behavior & temperament
Peaceful, energetic, and best kept singly or in groups of 5+, since small groups of 2-4 can squabble. Excellent in community tanks with tetras, barbs, rasboras, and gouramis. Avoid confusing them with the more aggressive true flying fox or the false siamensis, which have different markings.
Health
Hardy and disease-resistant; ich is the main concern under stress. Being a true cyprinid with scales, they tolerate standard medications better than loaches. Good diet and stable water keep them healthy for many years.
Tips, DIY & hacks
Verify true identity at purchase: the genuine SAE has a black stripe extending into the tail and lacks a second gold stripe. Add them early to a tank with a black beard or hair algae problem for the best clean-up impact. Keep 5 or more to avoid intra-species nipping seen in pairs and trios.
