blue tang scratching

Hi everyone, We are new to the saltwater aquarium hobby, had ours about 3 months. We got a blue hippo tang about a week ago, she seems to be doing fine but today I've noticed her tilting to the side when she swims sometimes, and has also been kind of scraping or sliding against the rocks. Is...

I have a small blue tang who has always scratched himself since introducing him about 3 weeks ago. But his scratching has gotten worse and now I don't know if he is scrapping his scales off or if this is marine velvet or what. ? He eats well and is active. I've never been able to spot or watch...