Moorish Idol - Take 2

[gobytron]

Originally Posted by Samw

Are lights off? if you have your lights on and have algae, you would be getting O2 from photosynthethis from the algaes in your tank.

Even so...
it would seem you two are reporting extreme oxygen sensitivity.

Where do you draw the line for the threshold?

Now it sounds like the average set up with some algae, overflows and such would almost certainly be able to maintain appropriate oxygen levels.