[jballs1778]

Hi i have had a problem with some of my fish dying. I am new to the hobby and have a 24 gallon aquapod tank with 30lbs of live rock and 40lbs of live sand. I have 2 cleaner shrimp, 1 fire shrimp, 1 sand starfish, 5 hermit crabs, 1 damsel, 1 clownfish, a bulb anemone, a hammer coral, and a purple and green flowery coral. Anyways all of these fish seem to thrive and be great in my tank, however i have had a flame angelfish die, and a sailfin tang die. The angelfish developed white spots on his fins and head and the cleaner shrimp were all over him, it was the same thing with the sailfin tang, but neither the clownfish or damselfish have had any problems and they have been thriving for about 2 months now, but other fish that i try to put in get this disease. I am unsure as to how to go about getting rid of whatever is in my water. I have done 50% water changes but that still didnt help. Any help or information would be greatly appreciated. Thanks