The two fish are very closely related, but there are actually some major distinctions between them!  It can get a little confusing—so let's set the record straight. Here's a breakdown of what you need to know: Both mahi-mahi and dolphin fish, also known as dorado, belong to the Coryphaenidae family of marine fishes and can be found in warm waters worldwide. They're also both marketed as "dolphin" or "dolphin-fish." However, there are several key differences between mahi-mahi and dolphin: Dolphin fish, also known as Mahi-Mahi, are mainly found in temperate waters worldwide.  The average adult weighs between 5 and 10 pounds but can grow up to 40 pounds!  They have slender bodies with large heads, slightly downturned mouths, long dorsal fins with no spines, and silvery sides.  Mahi-mahi, on the other hand, is found in tropical and subtropical waters and can reach up to 100 pounds!  They have a stockier build, with a smaller head and a more upturned mouth. Their dorsal fins have spines, and they are a duller silver color than dolphins. Mahi-mahi is also called dorado, a Spanish word that means "golden." Dolphin fish have no other common names. So there you have it! While they may be related, Dolphins and Mahi-Mahi are two distinct fish species.