Hey guys n gals got a problem hope someone can help. Bought a humbug damsell a few weeks back after a few days in the tank the damsell broke out with white spots all over it, after taking some pictures to lfs they agreed it was white spot and gave me some stuff to dose the water with, last week the humbugs white spot seemed to be on the mend but the fish looked stressed heavy breathing not eating or anything, from what i could see none of the other fish were pestering it, i have 2 clowns, a dottyback, a yellowbelly damsel and a purple firefish who all seemed fine until today, now one of my clown fish is looking very stressed breathing fastly and not eating, all other fish look to be fine, i have checked my water and amonia is at 0 nitrite 0.5 and nitrate all seem to fine i dont know what to do now, can anyone help????

Thanks

Stephen

Hopefully they havent died yet. But ALWAYS quarantine a sick fish before medicating ESPECIALLY saltwater. Most of the meds they sell contain copper which will kill your inverts. You may end up with a full outbreak of white spot on all your fish now that you've had it in your main tank. The meds may have made the other fish sick so that's why you quarantine when medicating and when adding new fish.
Right now though, do water changes and check those parameters. Since your nitrite was still 0.5 that means your tank either went through a mini-cycle or it was not fully cycled. This can cause your fish to stress.
I suggest buying a 10 gallon that you will use to add your new fish until you know they arent sick (unless your fish are too big to live in that, then upgrade from there).
What is your salinity and Ph also?