Everything's A-ok now, all symptoms have subsided.
I haven't checked ph in almost a year because my tap comes out at 7ph and aside from a small bit of driftwood, nothing should really be lowering ph (or so I thought) and I've been told consistency is more important.
It's a pretty heavily planted tank, but it's been up and running for quite some time now. I think I'll scoop out the substrate and give that a deep cleaning to try and fix the acidification.
I'll also toss back in my seiryu stones which I've read raises ph.
I've skipped a week or so here and there of water changes since I started using the canister filter because I thought me quadrupling the pre-exisitng filter capacity would keep the paramters in a good spot for a longer period of time. But obviously, filter's don't do squat to ph.
So this is a bare bottom tank?
So when you moved from hob to canister a month ago did you bring seasoned media (bacteria colony) over to new filter or run both filters long enough so that new canister got colonized?
Yup, I tossed in all the old media as well as used a bacteria booster for a few weeks, so it should at the very least be functioning as well as the filter I was using previously.
Bump: Well this has been a learning experience for me.
I've always thought the process fish get affected by bad parameters as
[Bad Parameters] -> [Unhappy Fish] -> [Parasite/Bacteria/Fungus attack] -> [Sick Fish]
But this time, the symptoms seem to have been caused directly by the bad parameters.