The only native freshwater fish in Hawaii is the oopu... a kind of gobbie. Everything else is intorduced.
Largemouth, smallmouth and peacock bass. Bluegill, channel catfish, oscar, carp, talipia, and snake head, rainbow trout and prawns were all introduced by the state.
Every thing else got into the streams and lake by someone dumping their unwanted aquariums. Tropical fish really grow big when they are not confined to a small place.