Fish all dead but one who is dying

[rich nyc]

I came home and found my clowns and royal gramma dead and my filefish barely breathing. Noticed water was dirty with blackish floaters and my return pump was not working. Not sure for how long but fortunately had one around. Not sure if that did it or was it velvet.

 

[Big G]

Sorry for your loss. Doesn't seem like that small number of fish could deplete the O2 that fast. Is anything new to the tank in the last 30 days or so that is "wet" like corals, fish, snails, etc?

 

[deedubz]

Sorry for your loss man.

 

[rich nyc]

So it is weird because my file fish that was breathing did not die. I decided to place him in water from my fuge and an hour later was up and swimming so I put him in my display tank and seems to be just fine now. Not really show how to explain it.

This is in my nano tank 20gallon im penninsula

 

[Maggie321]

What's the temp? Did your heater fry or could the failed pump have overheated them and now the water is cooling back off?

 

[rich nyc]

79. I think the pump may have failed awhile I ago and i just noticed because there is much more water circulation with the new pump. It was less then a year old. amazing how the coc is always unfazed.