What is this?

[Blueberries]

Could this be an anchor worm? I’ve been dealing with fin rott and have been treating with aquarium salt. They seemed to be doing a lot better since I switched to a different kind of spring water ( I still use water conditioner). We have been going in a positive direction until this evening when I saw my orange guppy developed a bump with something white sticking out of it. What do you think it is?