today i came home from work and found that 2 fish have white spots all over them. i think one also has fin rot (half of her tail is gone). i have had them for over a week now. there is 4 platys, 13 fry, and 1 pleco. the fry dont have any spots on them nor does 2 platys and the pleco. the fish have been fine until today. what can i do that wont harm the fry if there is anything? the temp of the water is 81 degrees. i do a 25% water change everyday.