My 3 fantail goldfishes have ich, i just bought aquarium salt and need to know how much salt to put in?? help!?

alright i had the same problem a couple months ago. the salt is okay but ur best bet is to go buy fungus treatment for fish which you can find at any petco or petsmart or even the place where u got ur fish. this will heal ich and many other fungus problems fish can get that is wut i did and it cleared up in a couple days and heaters are not needed for goldfish. hope this helped