Chinchilla not eating

Hey guys my 5 y/o chinchilla hasn't been eating much for 3-4 days. He doesn't touch his pellets or hay. I fed him three whole wheat Cheerios and a bit of rolled oats because he usually loves those but he didn't seem that excited and wouldn't take more than that. He's drinking a little bit of water but not too much. He is less active than normal but still runs a bit on the wheel and approaches me when I come to the cage. He's been posing less frequently obviously due to not eating as much. Physically nothing looks different from the usual. And other than the things I've described nothing else is different; his breathing seems fine, he doesn't seem in pain (or he's not bee very vocal about it), and there's no fur loss or anything. I may be taking him to the vet tomorrow but I've never done that before because he's never really had any issues. If anyone has any suggestions on what may be wrong or what I could try that would be great. Also, if anyone knows of good exotic vets in the York region area in Ontario, Canada (Richmond hill, Markham, Newmarket, Aurora, etc.) please let me know! Thank you.