Ich is Always in Your Aquarium
This is my absolute favorite one. And probably the most common one. There are many reasons for this myth, but all of them can be defined and eliminated by understanding the life cycle of the parasite in question. ICH must have a host to live. It does not have a dormant stage, it cannot survive in a tank without fish for more than a few days at tropical tank temperatures. Even in very cool water it is limited to 1-2 weeks at the absolute most. ICH does a good job of hiding from hobbyists who don’t know what to look for. It also does a great job of sneaking into your tank. It cannot spontaneously appear, and it cannot live without a host. Many fish are highly resistive to ich, however the gill area of a fish is not protected in the same manner as their skin. It only takes one free swimmer to attach to the gill to continue the life cycle and allow ich to remain in the tank. Like many parasites ich prefers the gills. This makes a lot of sense, given that the gills are full of food, they are reasonably soft, and they are not protected with scales and slime coat. ICH cannot be seen when on the gills however a fish with irritation will flash and scrape their gills. This sign should never be ignored. ICH is not the only thing that will cause a fish to flash or scrape, but when a fish does this there is almost always something amiss so careful observation and diagnosis is in order
