Originally Posted by Mean Harri
Ich, the parasite, is unaffected by medications until it leaves the fish.
Higher temps speed up the life cycle of Ich. There is about a 3 day window to get the parasite killed with meds before it surrounds itself with a secretion in the gravel after leaving the fish and respawns to attack again. Once back inside the fish it is untouchable by meds in the water. Thus the longer treatment regimen and recommended raising of temp. Just an fyi. While ich is stressful as is raising the temp, the higher temp is not as much stressful as most tropical fish can handle the higher temps. Lower temps extend the ich life cycle. http://freshaquarium.about.com/cs/disease/p/ich.htm
this is all very good information and i agree with it.
raising the temps speeds up the life cycle and it is one thing you can do to speed up the treatment. you have to catch it in its free-swimming stage and that could take you a week or more at lower temps, and you would have to treat all that time. raising temps can shorten the life span significantly, and can outright kill the ich if your fish can tolerate very high temps, but that is varying. it is true that higher temps will lower oxygen levels and could add stress to your fish, but there are things to make it easier for them. first of all, leave the lights off during treatment unless you are observing for symptoms. also, you can drop the water level some to create more surface agitation and that will help with oxygen levels. you could also add an airstone.
rid ich is a very good medication, but it has some drawbacks. it will stain the seals of your tank blue, and you could also notice it on your decor. so, it is best to take things out that you wouldnt like stained. for this reason and more i like to set up a hospital tank. you can use a cheap ten gallon tank or even an old cooler or large plastic bin. a hospital tank helps lower the amount of water you will need to change out during treatment. just move your filter to the hospital tank. what i like most about doing that is that in your main tank, without any fish in it, you can raise the temps as high as you can, and without a host fish present, all ich in the tank will die within days. then, you only need to treat the ich that are actually present on your fish...i hope that was clear. make sure you remove any carbon during treatment, and add it afterwards to absorb any meds.
that said, you need to figure out why your fish are getting ich. ich is pretty much always a result of stress. if you have had four outbreaks there is probably something going on that is causing stress.