The emperor loach (Botia udomritthiruji) is a small freshwater fish in the loach family Botiidae native to the Great Tenasserim (Tanintharyi) River Basin in south Burma. It reaches 13–15 cm (5.1–5.9 in) in length, and the female's abdomen plumper than the abdomen of the male.This fish species was first caught about 1993 and was identified only relatively recently. It lives in the Tenasserim Hills, in the upper Great Tenasserim River drainage area.