http://angelfish.net/VBulletin/showthread.php?t=28878
should be a big help to understanding things here in this link
good luck with your fish
should be a big help to understanding things here in this link
good luck with your fish
Hole in the head is caused by poor water quality and can never be fixed and there is no real cure for it you can only help to improve/reduce it.
Keep the water quality at it's best and vary the diet from time to time, live food for example now and again will help keep fish in good condition along with good water quality.