A hospital tank is what is needed when treating a fish who is sick with
any illness. You don't want to infect the other fishes in the tank. Ick
is caused by stress to the fish. A hospital tank is also useful when
buying a new fish and getting him acclimated before he goes in the main
tank, also to make sure he's not sick and bringing a disease into your tank
A fresh water dip will cure the fish of the ick right away. A cleaner
shrimp will also cure the fish,but may take a bit longer. A U.V.
sterilizer? from everything I've read, is not recommenced in reef
environment. It will kill ALL bacteria even the the ones you want in
the tank.
Sometimes doing a little research on you own, will answer the very
question you seek to answer.