It is very unsafe to give fish with bones to a cat. A cat can choke to death on one small bone if it catches in the cat's throat.

http://wiki.answers.com/Q/Can_cats_eat_fish_with_bones

Can cats eat fish with bones? In: Cats

Answer

It is very unsafe to give fish with bones to a cat. A cat can choke to death on one small bone if it catches in the cat's throat.

http://answers.yahoo.com/question/index?qid=20080229082542AAmzoNM

My kitten died when she accidentally choked fish bone, for the next time, what can I do?

I thought she was just playing, until I realized she wasn't, and hardly gasping for air. I held her, her body is very weak, as she is dead, but she's still making "meow" sounds. I quickly opened her mouth, and pulled the bone that I realized was inside her mouth-closing her throat. But sadly, she died. I don't know if she was, so I made a -some-like-CPR, I blew into her mouth with a straw, but she didn't response. Now, she's dead.