First picture in the link has a gold ram. Left pectoral fin has a white spot on the outer edge. Tail has a possible white spot on the outer edge near the middle. Possible white spot on shortest fin ray of anal fin.
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Keep the temperature at 86F for 2 weeks. If it is whitespot, the temperature will kill the parasites, but you need to keep it at 86F for 2 weeks continuously.
If you lowered the water level to allow the filter outlet to create more surface turbulence then that is fine. However, when raising the temperature of the water it is a good idea to use additional aeration from an air pump/ airstone to try and maximise the oxygen in the water.
It's also a good idea to clean the tank, filter and gravel before raising the temperature. This reduces the rotting organic matter (fish poop) and leaves cleaner water for the fish. Doing a big 75-90% water change and complete gravel clean will reduce the number of parasites in the water and substrate and leave fewer behind to infect the fish.
Make sure any new water is free of chlorine/ chloramine before it is added to the tank.
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There is more info on whitespot at the following link. The first post on page 1 is more technical, the last post on page 2 is more for beginners [emoji4]
http://www.fishforums.net/threads/what-is-ich.7092/page-2
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Corydoras naturally take air from the surface. They swallow an air bubble and it goes through their intestine and helps give them some buoyancy. They also absorb any oxygen out of the air bubble when they swallow it. If you watch closely you might even see them fart bubbles