2 weeks ago i added 3 female bettas into my 50 gallon tank along with my pleco, crayfish, and other female betta. everything was fine for the first week and then in the middle of the second week the 3 new ones died. i took a look at my original female betta and She had cloudy protruding eyes and scales and she was covered in gunk, same with the pleco. I thought i could have been dropsy but she wasn't bloated and neither was the pleco. i took my water to my local pet store to get it tested and they said everything was good except my ammonia was a little high. i told them about my fish and they said it was probably fungal so i treated the water but nothing worked. now today, my betta passed and my pleco is still sick so i did a full water change and cleaned everything. i thought it was just high ammonia so i put my cray fish and pleco back into the clean 50 gallon tank, but after a couple hours the water is foggy. there is a scratch looking thing behind his right eye like he scraped himself and holes in his fins and he has red streaks and spots. ive been doing everything and looking up stuff but nothing is working. i just want to save him but idk if its too late and hes just suffering. i have a filter and heater and everthing you need to balance your water.