Percis matsuii is a fish in the family Agonidae (poachers). It was described by Matsubara in 1936. It is a marine, deep water-dwelling fish which is known from southern Japan, in the northwestern Pacific Ocean. It dwells at a depth range of 200 to 500 metres (660 to 1,640 ft), and inhabits sand and mud sediments. Males can reach a maximum standard length of 15 centimetres (5.9 in). Due to its moderately wide distribution in its region, and due to a lack of interest from fisheries, the IUCN redlist currently lists P. matsuii as Least Concern.