I recently picked up 3 fish from an extremely crowded 75 gallon. All three were eating well and had been in the tank over a year. I treated with Prazipro, then added to the display. All my fish have bright clear eyes. All three of the fish I got have cloudy eyes. It is not severe, just not clear like my fish. Regal Tang, Purple Tang and Majestic Angel. All are fat and eating like pigs. Any ideas/suggestions/causes/treatment/thoughts?