what are the most common fish desease?

[calvindo]

i've been reading on fish desease to prepare myself, in case i experience it. The most i've found is "ick", some says its not cureable. my question is, once your entire tank is infected, how do you get rid of the parasite?

 

[bdhough]

I've heard in the past that every fish has ich and its just a matter of the proper conditions bringing it out. I don't know if thats true or not. It is probalby the most common disease and the most treatable disease. Once ich is in the system all your fish need to be taken out and treated over 3 or 4 weeks. 4 to be safe. This gives the disease a chance to die in the display while you manually take care of the disease in a QT tank. This is very tedious and HARD since its very difficult to pull a fish out of the display unless you can sneak up on him. All the more reason to QT a fish before placing it in the tank.
EDIT: there are alot more diseasees and parasites than ich. Fin rot, marine velvet, red/black ich(which goes by a name i can't remember), cloudy eye, plus more....

 

[calvindo]

does the qt tank require a full time filter and all the works? skimmier, heater, sand, lr etc...?
also, how does someones tank get infected with this desease? is it because introducing a ick infected fish to a tank?