About 2 weeks ago I introduced the panda cory into the tank. I suspect that may have resulted in
ICH, because about a week ago I noticed a small white spot on the nose of one of the male rosy barbs. Then a couple of days later I noticed about 4 white spots on the female rosy and yesterday I saw one or two dots on the other male. I'm guessing it's ich because it does look like a small white grain of salt, but there are relatively few spots, not the dusting I've seen and read about. Plus the fish seem to be behaving normally, not scratching up against things.
I have a few questions. If this is ich, can it be controlled / eliminated simply through water changes and raising the temperature? I checked water quality yesterday and
ammonia and nitrites were zero. I couldn't get a good read on the
nitrate level, but I think it was near 40
PPM. I did a 25% wc, so everything should be okay.
pH was 7.4. I raised the temp a bit and have it at about 80.
I don't want to medicate the tank if I don't have to, especially considering the fish are not entirely covered by white spots. But if that is the only way to cure the problem, what is the safest and most effective considering I have the cory?

Everything I read indicates all the best ich cures, including salt, malachite green, etc, are harmful if not fatal for the cory. I bought some CopperSafe (copper sulfate), but later read that catfish might absorb it and be harmed by that, so I have not added it (yet).
Please let me know if anyone has any suggestions or can refer me to a good website. The information I've found has been contradictory or doesn't give me a complete answer for my setup.
Thank you.