If your going to feed your baby salmon or other fish, be careful if he's male, since sometimes fish products can actually cause urinary tract infection if eaten in any great quantity with male cats.
Females are lucky, though, since they have nothing to worry about.
But if your going to give your fish treats then do so with great moderation, and not often. My mom almost lost Fritti (her little kitty boy) because she loved giving him tuna and salmon whenever we had any, which was often.
I'm not sure how common this problem is, but our vet had reccomended that one should stay light on fishy products when you have a boy kitty.

If you want to give him treats, though, you can always get turkey or ham or chicken pieces (shred it for them, and make sure its all natural with no additives or preservatives added when they cooked it or prepared it for sale).
We normally only go to health food stores, so whenever I make a sandwich I'm always sure to give my babies a tiny strip of whatever lunch meat we have.