While the Hawaiian term “mahi-mahi” is probably the most common label for this fish, it's hardly the only name you might see. The species is Coryphaena Hippurus, and the Spanish name is Dorado. It's sometimes referred to as a dolphin fish, but there's no need to worry. Mahi-mahi is definitely not a mammal, and it's not in the dolphin family. Although there's no direct substitute for mahi-mahi, some fish have similar properties. Since mahi-mahi is a saltwater fish, it's always best to use another saltwater fish as a replacement in recipes. White-meat fish such as halibut and swordfish are the closest in taste and texture. Even though it's a red meat fish on the oilier side, tuna can also be a reasonable substitute for mahi-mahi in a pinch.