I am new to the hobby and my wife and I were so pleased with our tank. all the fish were fine for a couple of months and I did a stupid thing. I bought a fish from a GUEST that said it was being chased by another one of his fish and he wanted to give it a good home, so we went and picked him up. Due to my inexperience i didn;t take much notice of the spotty and dull color of the fish, I thought he was just stressed and need a good healthy enviroment and he would get better. 3 days after getting him I noticed 1 of my matched pair of blakc clowns was starting to stay at the bottom of the tank [again inexperience I didn't take any action] the next day the clown was dead. I begain to get a little worried then the second black clown started swimming at the bottom of the tank, the next day he was gone. I payed $150 bucks for these but it wasen't the money, it was the lose of the fish that hurt us. then we started noticing our orange clowns getting spots and looking a listless and swimming at the bottom of the tank. they are eating fine but they go to the bottom of the tank after word. We also noticed our Coral beauty taking on the same symptoms. the Coral beauty was dead the next day, the Clowns are hangin in there. I have a 6 line wrasse and 5 Chromis and a Blue tang [that we are very fond of we do not want to lose this tang] that are not showing any signs of the spotting but the tang is rubbing up aginst the live often. He still looks good but [this could be my imagination] I think he is breathing heavy or his gills are working harder. they are all still eating good. after doing some research on the web and looking at several photographs I am 95% certain they have Brokklynella. I also have several high dollar Corals in the tank a cleaner shrimp and 2 anemone. Can someone please tell me there is something i can treat my tank with that will not kill my coral and tarnish my tank for life and hopefully save the fish especially the tang. I unfortunately do not have a quarantine tank and do not have the money to start another tank for that right this minute. I hope someone has something that can help. also if there is nothing I can do to save the Fish will this kill my coral and linger or stay alive in the tank thus making the tank uninhabitable? please help!!