Siamese flying fox

The Siamese algae eater, also called the Siamese flying fox, is a tireless forager from the fast-flowing streams and rivers of mainland Southeast Asia — Thailand, Cambodia, Laos, and Malaysia. Its most celebrated feature is an almost single-minded appetite for nuisance algae, particularly black brush algae (BBA) and hair algae that many other fish ignore. Identification is key: the true species has a single bold black stripe running from snout through the entire tail fin, with slightly serrated edges and completely clear, unmarked fins — distinguishing it from lookalikes like the false flying fox or the more aggressive Chinese algae eater.

Siamese algae eaters are active, fast-moving fish that do best in groups of five or more, where they establish a clear hierarchy and spend their days grazing rocks, driftwood, and plant leaves. Kept singly, they can become skittish; kept in pairs, mild squabbling is common. They are peaceful with tankmates of similar size — barbs, danios, rasboras, rainbowfish, and medium tetras all make good companions. Their diet in the wild is primarily algae and biofilm, making them herbivore-leaning omnivores. In the aquarium, they eagerly take algae wafers, spirulina-based sinking pellets, and blanched vegetables such as zucchini or cucumber, supplemented with occasional frozen foods. Overfeeding protein-rich foods makes them lazy and reduces their algae-grazing effectiveness.

Given their active nature and eventual size of up to 16 cm, a minimum tank of 200 litres is recommended for a group, with strong filtration, good water flow, and a secure lid — they are notorious jumpers. Water temperature should be 23 to 27°C with a pH of 6.0 to 7.5. They thrive in mature, well-oxygenated tanks with plenty of smooth rocks, driftwood, and robust plants. Breeding in home aquaria is extremely rare; most specimens are commercially farmed with hormone assistance. They are long-lived, routinely reaching ten years and sometimes fifteen with excellent care. An established group of true SAEs remains one of the most effective natural algae-control solutions available to planted-tank keepers.