Out of curiosity, would you recommend running an airstone 24/7 or on an as needed basis? It's an AIO, so I could probably tuck one in the back chamber somewhere, but the tank is in her home office, and I've yet to find an air pump that doesn't drive me mad with buzzing/humming.The water is a bit cloudy, most likely bacteria. The cardinal is flicking its pelvic fins a lot more than they usually do, not sure what’s up with that.
I still think this is/was a gas exchange issue - high co2, low dissolved oxygen or both together. Air stones are cheap insurance against that since measuring dissolved gas levels usually isn’t possible at home.
Jay
Going back to the earlier talk of surface agitation: I honestly felt that she had adequate agitation. Do you have any example videos of what would be considered "ideal" shy of an airstone? She is by no means ready to run out and grab new fish to replace her clowns - she is quite upset about the loss - but I want to make sure we've got everything under control for the next try.
As always, I appreciate your help. You and @vetteguy53081 and @Saltyreef and the rest of this forum are wonderful.