Long story short, Have a 75g tank that we rescued back from mom inlaw. Was left with her four years ago and was well established. In the time we left it with her she added a undergravel filter??? stopped using the bioball system we had going and stopped adding any chemical let alone no water changes. Now we have it back home and it has taken two months to get it back where we want it. Now this tank has been established for a little over six years. We kept about half of the water and the substrate covered in the water during the move. Cleaned up the live rock that was covered in green algae, and removed the undergravel filter. Now we Have started to restock our tank and had alot of luck other then a hippo that got whitespot and a percula that also got it. None of my other fish had these spots or do now for that matter. So we waited about three weeks and my LFS replaced the percula for us and all was good for the first two days now he is showing signs of whitespot. Again none of my other fish have these spots. She did do a freshwater dip before we brought him home. I have done two since then in two days. This morning it looks like all the spots are gone. Should I worry?