Fat and skinny cat?

Okay... Billy is to the point of being TOO fat. He can't play with his dangle toy anymore, cause he can't jump high anymore. Too fat. But CJ is just ideal, and if she looses any weight, she will be under weight. Also, she's nursing, almost weaned, though, but still nursing. Billy HAS to loose weight, but I don't know how to without him eating CJ's normal food, or CJ eating his weight loss food. Will taking canned food away from him help?

I wouldnt take away canned i would give billy more the h2o should be filling for him

Does that mean I should add some water to it?

No
Just that wet food is 75-85 % h20 or broth thus greater volume in fewer calories...