Can anyone assist? I can't think of what else to do.. just like lost the big arowana and one of my biggest bass to this. Only readable water test is 10 nitrate. There is a slow drip water change constantly in effect, this is a very well established 400g tank - arowana, bass, Oscars, severums, datnoid, shovelnose and a couple different catfish. Bass are super lethargic and bottom laying, nobody has wanted to eat for a week. There was an unquartine snook (that was eaten by someone) added a couple weeks ago. Noticed red on pectoral fins of the bass so decided to do a general treatment.. erythromycin and general cure.. everything went down hill yesterday was the 3rd erythromycin and we lost the silver arowana that seemed good other than lack of appetite at the beginning. The bass are pale and bottom laying.. the dats and oscars seem fine other than appetite and minor eye fog.. the arowana looks like the skin has been melting off. I don't know what to do anymore just adding stress guard and praying.. what is this? Please don't be rude I've spent hundreds on medications I thought was best to do a routine treatment and I did it on all of my tanks.. this is the only one that this is happening..