Doggy is doing great! Tank has come alive - snails, stars, etc. are moving about regularly. Lost the urchin (as in, no idea where he went).
Water parameters test good. Just using cheap strips so won't bother pretending they are super accurate, but looks good enough at a glance. I'm never really concerned about specifics, especially in a tank like this as long as everything indicates its in a "safe" range. Still going to have a larger water change done this morning to be on the safe side.
So we probably just dealt with severely deoxygenated water over the weekend, and perhaps the Nautilus are more adept to dealing with low-oxygen conditions than some of the random life in the tank. A very scary lesson learned - airstone has been added to the DT.
Taking the water from the change and putting it in the 60G that is sitting empty next to it. Have some old LR I took out of a different tank (one with life removed, and left to crash) so going to let the 60G cycle for a few months before plumbing everything together and figure out some other interesting animal to add in.
@cuttlegirl - there are plenty of caverns in the rockwork, so I'm not likely to notice the cuttlebones. Also they'd be the size and color of some of the crushed coral so even harder to spot! Like I said, I have no idea how well they could actually develop in 65 degree water, although food was plentiful. I've also never had cuttles hatched directly in the DT, or released any when they were that small.