87 is generally the target for Ich treatment. If your heater is what raised your temp to 92, then back the heater down until you are at 87-88. If the temp is 92 due to the weather, then you REALLY need to find a way to cool things down a bit. Less light, especially in the middle of the day, a fan blowing over the top of the tank.
Also, make sure you have LOTS of aeration going - 92 degree water holds very little oxygen for the fish.
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