I have raised the temperature to 84. The fish is swimming on the top and trying to catch some air. I think it is due to lack of oxigen. I have an air pupm. What do you think should be better, to lower the temperature or jost leave alone and maybe do water changes more frequently?
If you are already running an air pump, I'd lower the water level a little bit to let the filter agitate the surfac a bit more. If after an hour or so your fish are still gasping, then I would lower the temp. if increased surface agitation takes care of it then keep things as they are, or if you want take the temp on up. My experience with pictus is that they really don't like higher temps at all, but Others may have tried it successfully.
As far as 3-4 days, not enough time. it is normal to see in increase in spots after treatment starts. remember that ich is tiny when it attaches to the fish and then grows to a visible size. It cannot be treated or killed on the fish so any that was there when the treatment started will grow to visible size before they fall off to reproduce. Just keep things going and hope for the best. if you are 3-4 days into it then things should get better in the next couple of days.
dave