(Opsariichthys pachycephalus)
Opsariichthys pachycephalus is a species of ray-finned fish in the genus Opsariichthys endemic to Taiwan. It is one of the most common minnows of Taiwan, found in the entire western part of the island from sea level to 1200 m elevation. It is a small species reaching a maximum length of 16 cm (6.3 in) TL.