Haplochromis orthostoma is a species of cichlid fish that is endemic to the Lake Kyoga system in Uganda, where only known from Lake Bisina (a medium-sized lake to the east of Lake Kyoga itself) and Lake Nawampassa (a small lake southeast of Lake Kyoga itself and only separated by a thin swamp).[1] Its continued survival in Lake Bisina is questionable as it has not been recorded in recent surveys,[2] but it still survives in Lake Nawampassa.[1] This piscivorous species is peaceful among similar-sized or larger fish, but will rapidly swallow smaller fish with its very large mouth.[1] The largest officially measured specimen was in standard length, although it has been known to reach about in total length.[1]