I have a long 20 gallon tank, I did have 2 micky mouse platys, 2 male fire dwarf gouramis, 2 fire newts, 1 comet goldfish, and 1 pleco. Recently one of the platy's died, and I gave my goldfish and pleco to my grandmother as my tank will be too small for them in the long run. Now my 2 gouramis and the surviving platy are just kind of sagging. They swim very slowly about, hide often, and they all used to be very active fish. Any suggestions as to what is wrong with them? My readings are good and the tank is at 70-72 degrees. I am wanting to go get a few more fish, any suggestions as to what. All I have in mind is another platy, and maybe a neon blue dwarf gourami. I'm needing colorful and active fish, and also a bottom feeder would be good, as my pleco was getting much to large. Anyone know anything about gold chinese algea eaters?