TwoTankAmin
Fish Connoisseur
Do not assume its gone after three days spot free. Keep on treating for a week at least. You need to kill ich during the free swimming stage. You could still have cysts that hatch out new free swimmers. Its best to be safe rather than sorry.
From FINSWhite spot disease (Ichthyopthirius multifiliis) is caused by a protozoan with a life cycle that includes a free-living stage. Ich grows on a fish --> it falls off and attaches to gravel or tank glass --> it reproduces to MANY parasites --> these swarmers then attach to other fish. If the swarmers do not find a fish host, they die in about 3 days (depending on the water temperature).