If I was stuck in a locked room that was too hot, I guarantee you'd even hear ME hissing.
Does he have a cool-side hide too? (he should have) I'd lower his temps a little...& for sure check the humidity. (<that could cause noisy breathing too)
He only has a hot hide.. He is in an enclosed rack at the moment. The tub is a FB10 with the built in cup so two hides isnt really a possibility..
1.0 Orange Dream x Lemonback x Super Enchi -Damian