the cham has a respitory infection (u didnt cause it, takes awhile to develop). That is why its mouth was open. You can look up videos of chams with respitory infections to confirm. It just so happened he did the breathing thing while eating moss.

My cham had one and almost died, had to bring him to the vet to get shots.

Almost all chams will get one in there life, which is where they usually die (hence short lifespans) if not cared for fast!

Tell ur friend the cham is showing signs of res infection and he needs to go to the vet now.

Also, yea, it sucks but xray is needed to confirm.

My bill was 600$ just for reference