Sounds like you had a lot of fish for a 33, even with a skimmer and being temporary.

Your tank is a 33??? Your bioload is a disaster waiting to happen.

Sorry I didn't see the 72. But 2 tangs, 8 chromis, goby, damels etc?? You're still way over in bioload.

I agree that that seems like too many fish you might be ok if you had split the fish between the two tanks on a common sump.

Sorry about your loss


Brad

IME, 9/10 problems have been related to flow in one way or another. Not necessarily fish deaths but some yes.

No way those fish in a 33g could get the oxygen they needed if the only flow source was blocked. When oxygen deprivation occurs, the fish that needs it the most expires(dies) first. This frees up a little O2 but then ammonia kicks in. IMHO, if it wasn't a cycling tank then this deadly combination killed off your fish one by one.

:frown: Sorry for your losses

by the sounds of it the only thing putting oxygen into you water was your skimmer which you turned off for the night!

Still sorry to here....take now make sure you do a huge water change to get your ammonia levels down and to re-oxygenate the water!!!

it's all about the air stones!

sorry for your loss. I've had a few close calls with lack of oxygen problems.