I give my cats Starkist tuna in spring water all the time! I did not know it was not good for them. One of my cats only eats dry cat food, and, for some reason, it has to be Purina special care hairball treatment. The only other thing he wants to eat is tuna. It makes him so happy, so I usually give it to him. He has been eating it since he was a kitten (he's three years old), about two to three times a week. It has never made him sick or anything. All of my cats are pretty healthy right now. I don't want any of them to sick or anything, but they all really love tuna. Are you absolutely sure that tuna is not good for them? Where did you hear this? What should I do?