I'm not seeing the attachment. Do the white spots look like little grains of salt, or do they look like tiny fluffs of cotton? And are they on the fish or in it? I know some fish are more translucent than others. If they look like salt, it's probably it's probably ich. Do a water change and start raising the temperature to start. Isolating it won't help, you need to treat the whole tank. Depending on what other fish you have, you can treat with ich medicine and/or salt.