My one cat is very skinney. He isn't losing any more weight, but he eats all the time and isn't putting on more weight. He lost most of it due to the stress of getting a dog (who constantly tried to eat him for a month). We got rid of that dog and recently got another that is a puppy, and he seems more relaxed around this dog and he is eating alot (the same as our other cat) but isn't gaining weight like the other. He seems really healthy and likes to play and stuff still, should I be concerned(more than I am?)