How To Treat White Spot
Advanced White Spot
Ich is a very common ailment among cold water and fresh water fish. It looks like a light sprinkling of salt over the skin. In it's early stages it may not look like anything to worry about, but the disease can advance and overtake a tank, eventually killing the fish.
It is wise to treat ich quickly before it spreads and before it causes any deaths. Sometimes ich will only affect a few fish in a tank of many fish. Susceptible fish are the ones that may be more stressed than the others, or simply those who are more prone to ich in general. Ich is one of the few fish diseases where you should not quarantine fish because they whole tank will need to be treated regardless, even if not all the fish are showing signs of being infected.
What Is Ich?
Ich is a parasite, chthyophthirius multifiliis. This parasite attaches itself to fish and 'feeds' on it, excreting hystolites which thicken the outer mucus layer of the fish. Inside this layer, which is designed to protect the fish, the parasite grows until it becomes visible to the naked eye. This stage of the parasite's life cycle is the feeding stage. When it has fed enough, usually in a few days, it drops off.
Now in the wild, where fish can swim for miles and miles, ich is not such a big deal. The parasite lands, eats, drops and the fish carries on its merry way. But in a fish tank, things don't work that way. Your fish cannot escape the water where the parasite has dropped, and as the parasite continues its life cycle, swimming the water column before landing on the substrate where it reproduces. When the parasite sinks from the fish, it is called a tomont, when it bursts forth in its hundreds, and possibly thousands these new parasites are called tomites.
You see the problem here. The poor fish in the tank has now succored thousands of organisms, many of which will not have far to float before reattaching themselves to the fish and feeding again. Eventually, the fish will succumb to the sheer number of parasites trying to feed from it .
Treating Ich is a matter of killing the tomites. Ich medications do not work on the tomont or during the feeding stage, they only work to kill the tomites.
Understanding the nature of the Ich parasite is very helpful to understanding what you are doing whilst treating for it. It will also help you to prevent occurrences of this common tank pest, and keep your fish healthy for longer.