Batoidea is a superorder of cartilaginous fish commonly known as rays and skates, approximately 560 described species in thirteen families. They are in the fish subclass Elasmobranchii, along with sharks, to which they are closely related. Rays are distinguished by their flattened bodies, enlarged pectoral fins that are fused to the head, and gill slits that are placed on their ventral surfaces.
"The mahi-mahi or common dolphinfish (Coryphaena hippurus) is a surface-dwelling ray-finned fish found in off-shore temperate, tropical and subtropical waters worldwide. Also known widely as dorado, it is one of two members of the Coryphaenidae family, the other being the pompano dolphinfish.
The name mahi-mahi means very strong in Hawaiian. In other languages the fish is known as dorade coryphène, lampuga, llampuga, lampuka, lampuki, rakingo, calitos, or maverikos." - Mr. Wkipedia