i had 4 goldfish in my tank previously for about a year now.i thought about adding some other fish and bought three koi and two angelfish.an angelfish died the very next day of i don't know what cause.and a koi also died.and my healthy goldies also seem to be ill.i guess they have itch as they are scratching.im very tense as i had them healthy for a whole year and i don't wanna lose any of my fish.and also the angel fish isn't eating ANYTHING AT ALL.it just stays in a corner and whenever i put something for her to feed the other fish eat it.angel is very small about one square inch and the goldies and koi are large.i tried keeping the angel in a separate bowl but it didn't eat anything there too.PLEASE HELP ME I LOVE MY FISH TOO MUCH AND I DON'T WANNA LOSE ANY OF THEM.PLEASE.
yes i clean the tank regularly and feed them regularly too.they are not fed by anyone else and i do water changes with atleast 24hours stayed water and still add anti chlorine in it.i put salt in too.and also that blue medicine for white spots,velvet etc.we don't have any pets where we live.the koi with most itch is also becoming aggressive towards other fish as she's nibbling at their fins.