I have a 40 gal community tank. I wake up to find at least a few fish dead everyday. I found a platy that looked like she might have had a cut on her and maybe got infected and died. So treating with melafix. Ammonia0 nitrites 0 nitrates 20. Mollies guppies Corie's 2 angels betta platies shrimp. They have had no symptoms,all look healthy no acting odd or anything. Just dead!!! Helppppp!! Should I try pimafix too???