Hello, I have recently set up a new 55 gallon aquarium and I have my 10 molly fish and their fry in it. There was already an albino pleco and Mickey mouse platy living in it. The platy got a crooked spine and died two days later. Now almost all my mollies have the same white spot as pictured (letter a) and I am unable to find any info about this problem specifically. They all seem to be healthy, swimming and eating. Any help or info would be greatly appreciated.