You can find them live in Chinatown. Though the fishmongers are required by law to kill them after you buy. They breed them in ponds up on the north east side of the island. By Mokuleiea (not sure if I spelled that right...).
got the jag heres pic he was pciked on when young so missing part od dorsal but he's mean as hell attacks glass when you walk up on him lol if you got a decent size GT LMK maybe a pic also were around manoa stream you go to net them.