lost one fish to pop eye now one has hole in the head anythin to cure it?

[Finisher604]

I had the same issue on my ciclid 90 gallon tank. Bi weekly water changes of 20 gallon + filter cleaning and all the other stuff and it went Away

[Nano]

Wouldn't be Oscars by any chance would they? They are fairly prone to hole in head. But clean water is key
I also use a mixture of carbon, chemi pure elite, and phosban+ammonia remover in my canisters, then mostly bio and mechanical filtration in my aquaclears.