I have a 75 gallon aquarium that I've had for about 4 months now. I've been keeping the water cycled and everything is pretty much in balance in the tank. Originally, I had 5 blood fin tetras, 5 bleeding heart tetras, 3 lemon tetras, a priscilla tetra (I try to buy them in schools of five, but the petstore guys made a mistake). A couple months ago I added 2 clown plecos, 4 priscilla tetras, and 2 lemon tetras to even out the tank. A couple days later we had a massive death spree which ended in me loosing 1 pleco, 4 lemon tetras, and 1 blood fin tetra. We fixed the problem and for the past two months everything has been smooth sailing in our tank until Sunday. I noticed that one of our bleeding heart tetras was floating on the top of the tank dead and covered with a strange white-ish colored ooze. Then, I remembered that in the past death spree, the clown pleco that had died had also had this same ooze covering him. Of all the fish that died during this time, he was the only one with this stuff around him. What is it? Is there anything that I can do to fix it? Will my other fish become infected? Any help would be greatly appreciated. Thanks.