I said cobia... and cobia is good, too... I meant wahoo, or Ono depending on where you're at.
Wahoo, cobia, Mahi, snapper, grouper, in that order for me. Tuna is an altogether different subject and so different I have a hard time comparing it to other fish- same as shark or swordfish which is somewhere in between the two but different enough to be considered a totally different category imHo.