My dd is a seafood lover. We started her on salmon and shrimp at about 14-16 months and loved it. Since then she has had crab, clams in clam chowder, muscles, tuna sandwiches, and never has had a problem. My DH and I have no allergies to seafood so once we started her, it just took off.
DD also loves sushi(since she was 2), maguro is her favorite but she will also eat hamachi. I can usually fill her up with rice and edamame before the real sushi comes so it doesn't get too expensive! She will eat almost anything.
Have fun exploring new flavors!