Epinephelus undulosus, the wavy-lined grouper, brown-lined reefcod, mid-water rockcod, mid-water grouper, is a species of marine ray-finned fish, a grouper from the subfamily Epinephelinae which is part of the family Serranidae, which also includes the anthias and sea basses. It has a wide Indo-Pacific distribution. They are produced through aquaculture and commercially fished.