My Mississippi map turtle has white on half of his shell. At first it started small so I thought it was shedding so I ignored it for a few months. But then it got bigger and now its on half it's shell and not peeling off, I looked up fungus, shell rot etc. and from the symptoms it's not mushy or soft but some pieces on the edge are a bit fuzzy everything is hard and the white is a bit rough surfaced and doesn't come off at all. It's more noticeable when it basks and doesn't seem to effect it's behavior ( once I saw him yawn?) can someone tell me what it is and is it deadly??
