Hey guys. I got my 80 gallon tank running about a month ago, got it cycled perfectly and stocked it with multiple caves and fake plants. I also have a couple real plants in there such as moss balls and dwarf grass. I started out with Tetras, two common plecos and I love the little guys. I bought two angelfish today along with a RTS and almost immediately one of the angel fish got sucked to the filter. I pulled it off but it kept floating and only barely swimming.. after a couple hours I decided to bring it bac to the store. The lady refunded me saying a lot of the Angel Fish were sick. My second one, much larger looked to be fine but only stayed in the corner of the tank. It did not move when I fed the fish and was no tmoving well at all, only hovering right by the water line. I ended up taking it out and bringing it back to the store. My question is whether I should be worried about my other fish getting sick? Or is this a problem with my tank?