Anyone help?

One of my zebra danios has got really thin and it’s scales look like they’re lifting away from its body. When I’ve tried looking myself it just keeps coming up with dropsy but wouldn’t it be swollen? I think I would’ve noticed if it had swollen and gone back down again as this is mentioned when talking about dropsy too. Also the rest of the danios seem restless and are nipping at the other fish in my tank. I’ve attached the best picture I can get of the danio any help would be much appreciated