It's a testament to how much I love my dog that he gets any fish, because I really, really don't like it.
Anyway, Bailey get canned fish (I cook his food otherwise, though -- he doesn't get raw) -- sardines, pink salmon, etc. He gobbles it up, and it sure is easy to feed (no worries about calcium or anything). He gets fish oil pills otherwise, which he usually eats readily (which is also good, because once when I pierced one with a knife, it squirted all over my face, much to my extreme horror, lol).
My mom just bought him some frozen tilapia filets, though, so we'll see how that goes. I should have made her keep them and feed them to him at her house.