Even before I became vegetarian as teenager (with 16 iirc) I did not eat all animals my parents ate, not even the "you have to try it once" routine they tried to insist on. So while my parents both liked various crustaceans such as shrimp and crab I have never eaten any. I always thought they looked entirely too much like insects with their shells and legs, and those are thought of as gross here (not that that is rational, but I always thought you ought to put both either in the food or the non-food category for consistency). I suppose they didn't insist early enough so that I became used to the look, like I did with other food with a high grossness-factor to the unaccustomed.

With fish species I mostly only ate the trial bite and then refused to eat them from then on. The only fish I liked was plaice, but then that is most commonly prepared here in much fried bacon, so it really mostly tastes of bacon, and to a lesser degree trout. Whereas I found the carp which my father likes a lot icky (also I was always grossed out at the table because my father insists on slurping the eye, saying it tastes good).