Type locality of Ophiocephalus marulius ara, neotype in Mahaweli River basin, Angammedilla. Known from the middle and lower regions of the Mahaweli basin, occurs primarily in the deep pools in the Mahaweli River and its tributaries; also recorded from reservoirs in the Mahaweli catchment (Victoria and Randenigala). Around 20 juveniles (ca. 8.0-10.0 cm SL), guarded by a pair of adults, were observed in shallow water (ca. 60-80 cm deep), among submerged roots, close to the bank, at the mouth of a stream draining into Badulu Oya of the Mahaweli basin. The highest recorded elevation from which it was found was about 500 m asl at Kandy (Ref. 127648).