May be best to get some better pictures and re post. I can’t see anything. There’s a thread here about how to properly post for fish illness so the fish medics can help you.
The picture isn’t quite clear enough to see. It could be ich or it could just be mucus plugs. The background information is also vital. This post explains that:
Aquarium Fish Disease Problem Solving Determining the best course of action for a problem with your aquarium can be a difficult task. Even advanced aquarists will often need to seek the help of others for complicated or unique issues. Our intent here on Reef 2 Reef is to offer expert advice...