So I got a warm welcome into the hobby. And got death and destruction very quickly. So here's what happened. It all started with a change in rockscape. I replaced my old rocks. Bought new live rock from my local fish store. Never cured them, because I simply thought it would be fine. Turns out it was a super bad idea, and completely stressed my whole tank. I had 2 clowns and a Valentinie Puffer. I noticed they were kind skiddish for a bit but didn't take to big of a change to anything. Everyone was eating and everyone kinda calmed down later that day. Woke up the next morning, seen that both of my clowns had what seemed to be sand all over them. I figured it was sand. Because I did a rock change and water change the day before. Went to work to come home and find one of my clowns dead... complete shock to me. Tested my water and of course the Amonia was a little high, but not too too bad. So I did another small water change and cleaned the tank a little. But noticed my other clown still had sand on him and kept swimming into the wave maker. I couldn't figure out why the sand wasn't falling off. But took no further thought into it. Next morning my second clown dies out of no where. At this time I was doing alot of research, and everyone kept pointing their hands at the rock. The rock had die off that just harmed the fish. I took this and thought it was correct. So I did daily water changes. And just waiting for my tank to now "recycle" which it did. And now everything is testing good. Got home today 2 weeks later. And I now find "sand" all over my puffer fish and his eyes. Finally looked it up. And I believe it to be Marine Velvet. The only thing is. I have to treat it in a QT. And I don't have another tank I can use untill Thursday which is my next day off. I'm afraid I'm going to lose the last of my fish. And here is where the question forms. Is it possible that he can stay strong for a couple days ? If so how do I help em? Secondly, if the last remaining fish dies, how long do i wait for my tank to become disease free again? I still have snails, and a couple blue legged hermit crabs. Also coral in my tank which all are growing fantastic. Coral list: Xenia, Galaxia, Devils Hand, And Monti.