We surveyed fish fauna in 21 locations over the Rayu River system running t
hrough the Kubah National Park, Sarawak. In this study, we recognized 27 sp
ecies in 18 genera belonging to 13 families. Ambassis miops Gunther, 1872 a
nd Stenogobius ingeri Watson, 1991 were newly recorded. Pseudomystus rugosu
s (Regan, 1913) was rediscovered from Sarawak.