I have a 55g reef tank that I have had for almost 3 years now. I have never had any issues with the tank until the last six months. I used to have mushrooms, many feather dusters, snails, a crab and a chocolate star fish, BUT over the last 6 months I have lost all of these creatures. I have three fish that I have had since I started my tank back in 07' a domino damsel, blue devil damsel and a percula clown and have not had any issue unless I add any new tank mates all three are VERY aggressive. Recently I tried adding in another clown and a damsel both are gone now, not sure if the others had it out for them or if they were sick from the fish store they maybe lasted two months. Another thing, I bought some copepods off of ebay probably six months ago which never flourished. So I am thinking that introducing one of those probably added something undesirable to my tank. My fish are in great health but everything else has seemed to go to crap. I need some direction to get my tank back to where is was in the fall... Sorry to go on and on..