@wally war eagle I don't think so. JAZA has no listings of the species at Osaka Aquarium, and the body shape is different. In Mahi Mahi, the dorsal fin starts over the head, but the dorsal fin in the fish in the pic starts behind the pectoral fins.
I'm starting to think it may be the Green Jobfish, Aprion virescens. It has a similar body shape and colouration, and JAZA lists a holding of the species at Osaka Aquarium.
