Thanks for the reply, Cleo has already been to the vet when I first got him and he had routine bloodwork and a physical done and everything came back perfect. The panting and hissing only happen when he's about to go wild with his toy mice....he doesnt pant when just relaxing which is why I found it very strange that he did it only before he started to play....and hissing while he's playing and even spit today which was another first. Other than that he's a normal kitten, and VERY loving cause he purrs whenever he comes around to cuddle or when he's trying to wake me up with kisses and purring, pushing his nose into my face
