I bought 8 nickel to quarter sized silver angels about ten days ago. They all seemed fine for the first few days, then I noticed one was off by himself almost all of the time. (day 5 maybe) then the next day, I saw that he was sort of gasping and still not hanging out with the rest very often. I think that he was eating, but the next day he was dead and I removed him. The next day, a second fish began behaving the same way and was dead the next day. 2 days go by and I notice a 3rd angel is behaving like the first 2 on their last days. He was definitely eating, but he did have a clear/white poop strand for about 2 days. Today I found him dead at the bottom of the tank. I think that another one has distanced himself and may be on his last day.
What can I do? is it a parasite? I tested the water, it's on the hard end of the spectrum, but everything else seems fine.
Please help.
*Video available upon request.
