I live in a fishing community in Florida. Here is what I see and have learned in my area. May be different elsewhere though.
Shellfish- most is caught on these fishing boats that stay out at sea for days on end. They spray clorox and other stuff on the shrimp and stuff to keep it pink.
Lobsters and crabs are bottom feeders, so ick.
Most tropical fish like groupers, yellowtail, dolphin ( mahi), pompano, stuff that gets really big may have ciguatera toxin ( just had a breastfeeding mom get it and need help, it was awful)and that does not cook out and no way to tell ahead of time. But aside from that, I would stick with groupers ( small) dolphin, yellowtail,tile fish,- small saltwater fish.
And the bigger game fish like tuna, swordfish and the like have the mercury debate.
So, when my husband fishes or shrimps he is selective about types and sizes. Small backcountry fish like snapper or small dophin. No filter fish like crab or lobster and he only eats shrimp that he catches.
I am a vegetarian, and the kids are too. Before though, I would only eat what we brought in or a friend did. Nothing off of a fishing boat and no game fish.
( if I wasn't veg)I would never eat fresh water fish. Too much contamination.