flatu

Flatu is a small genus of freshwater goby fish that belongs to the family Gobiidae. First described by ichthyologist J. A. Smith in 1954, the genus comprises four species that are endemic to the tropical river systems of Southeast Asia, particularly the upper and middle reaches of the Mekong, Chao Phraya, and Red Rivers. Members of Flatu are characterized by a laterally compressed body, a fused pelvic fin that forms a suction disc, and a distinctive scale pattern of dark crossbars. The largest species, Flatu maximus, grows to a maximum total length of approximately 12 centimetres, while the smallest species, Flatu minimus, reaches only 4 centimetres.

The ecology of Flatu species is typical of benthic dwellers: they occupy the bottom substrates of slow to moderately flowing streams, preferring sandy or silty bottoms with scattered vegetation. Feeding primarily on small invertebrates, these fish play a role in controlling benthic arthropod populations. Reproduction occurs during the monsoon season, with males guarding the eggs on the underside of rocks or within crevices. While local fisheries occasionally capture Flatu species for use as bait or subsistence food, they are not widely traded commercially.

Conservation assessments have been limited; however, the ongoing degradation of freshwater habitats in the Mekong basin, caused by dam construction, pollution, and overfishing, raises concerns about the long‑term viability of Flatu populations. Continued field surveys and population monitoring are essential for determining the conservation status of this genus.