Thanks for all your advice
I am feeding him Pure Vita its the salmon and potato formula. I wanted to get him orijen but unfortunately it was sold out. I have read a lot of good things about origen on this forum. Pure vita seems to have good ingredients and the guy at the store told me that the salmon would help with his skin.
I read online about satin balls. I have him some and he did put on a little of weight but now hes back to being thin.
He's healthy. He's been checked for worms and I give him Interceptor once a month.
I guess he's just the skinny type.
When people tell me he's too skinny sometimes I joke that I wish I had that "problem" lol