I read that the parts of the Giant Trevally can be poisonous. They are in the Jack family.
I used to fish for big Trevally from the beach at night in Kailua Oahu when I was a kid. biggest one I caught was 62 pounds. Good eating (ono) In Hawaii they are called Ulua. and yes they are in the Jack-Pompano family. We used squid as bait.