Aw, thanks misterking.
I've learned so much from being involved with this forum, and hope that I can give a little bit back, 'specially to newbies who want to learn from the mistakes we've all made. Like mine! Account for your fish!
Yeah, I guess it's not
that awful. Missing the dead cories for a few days, because I was so worried about how my angels were working, is probably the worst thing. That's the only thing that I can think of that affected my nitrates. Fortunately no one else looks to be off at all.
Overstocking or mixing possibly problematic fish really requires being super observant (duh, hypocrite over here!), regular - no skipping! - water changes and other maintenance, plus being willing to rehome fish that aren't working with each other.
Sigh. I still feel like I suck a bit.