I thought that it would be a little easier to help if you could see what I'mk talking about so I inserted a couple pictures. The white spots I'm talking about are right in front of the gils.
I have a 55 gallon freshwater tank that has been set up for going on 5 months now. I have 7 guppies, 1 orange lyretail molly, 1 dalmation lyretails molly, 2 cory cats, 2 zebra danios, 2 neon blue gouramis, 2 sharks(Iforget what they're called), 2 common plecos, and 6 black phantom tetras. I tested all of the levels in the tank when I noticed it and they were all normal. I did my last partial water change 2 days ago.
What would be the best thing to do?