Thanks Jay - really appreciate it. Planning a very large water change today and have carbon and cuprisorb running.Thanks, the videos help rule out some things....notably, the fish are swimming well and not breathing fast so that rules out Brooklynella or Velvet. No spots, so that rules out ich. that just leaves flukes are a possible disease entity. Trouble is, the possible contamination of the water adds another layer to all this.
If you want to pursue the fluke angle, you should get the copper issue under control and then you can dose the tank with prazipro - no UV or carbon, with good aeration. Dose once, then wait 8 days, change 25% of the water and dose a second time.
Jay
I did notice this morning some largish spots on the tail of the remaining Sleeper Goby. Not sure if flukes would display on fins like this? otherwise the fish looks healthy. Don't see these on any other fish at this point.