The term 'moonfish' can refer to two different species of fish. The first is the OPAH, which is a large, deep-bodied fish found in tropical and temperate waters around the world. It has a distinctive red color and is highly sought after for its delicious flavor. The second species is the opahs, which is a smaller, more slender fish found in the same areas as the OPAH. Both species are popular among anglers and commercial fishermen alike.