So turns out I did have a nitrite spike after all. I checked up on the evacuated cories this morning and at first I thought they were dead. They were not moving upon tapping the tank and I saw no gill movement either. I poked them with a net and there was minimal and sluggish reaction from about half.
I immediately dosed with methylene blue. Instant effect, they were happily swimming about again a few minutes later. I counted three times to assure myself the swimming group was still complete. Though little buggers.
Popped in a few air stones, I'll have to keep dosing MB for a good week at the very least. Eh. Poor things
Still don't understand where the spike came from.. A PH drop by itself shouldn't kill your bacteria if it is still above 7, right? I can't help but think something happened to my cycle somehow...
But it must have been pretty sudden. There is no way the pandas would have lasted through several days of >2ppm NO2.
Also holy cow. That is some next level camouflage. And here I thought my kuhli's and oto's were hard to find in a well-planted tank. Pst.
KuhlI loaches don't camouflage, they just outright disappear! sorry to hear about your problems with the tank, though I'm glad your Corys are alright. I just realized the other day how badly I'd neglected my Betta tank these past few weeks, and I feel so terrible about it.
