Our instructions might be different because DH is severely allergic to shellfish, but our pedi said to start with fish sticks. He said the minced fish in there is so processed that it's less likely to trigger a reaction.
I would say it depends on the fish. We are pescatarians, but I don't feed my girls cod, which is what is usually used at a fish fry. My sister can eat all other fish but cod, which apparently is a common one to be allergic to. (First hives, then swollen throat and tongue to where she can't talk) Something like halibut is good since it is a less likely fish to be allergic to and I would say go ahead!
Patrick has had tuna, crab (and Krab), shrimp, scallops, oysters, flounder, catfish, and even sushi. If there isn't a history of allergies in your family I would say you are in the clear.
Re: Dumb question here...Fish
Our pedi said that fish is fine (any kind). She said that after 1, the only dietary restriction is peanut butter.