Has anyone heard if this works? I was told to do this by a friend who used to work in a pet store...... He said to put a handful of pennies in the tank and it will never get ick but what will happen to the fish?
You really don't want to put any kind of metal in your tanks except aquarium safe aluminum or stainless steel.
Some medications have copper in them but it is not safe for all fishes and only stays in there for a short period of time.