Totally agree, Matt.
What a morning!
Everyone was alive and well when I got up. However, after my breakfast, one cardinal was breathing very fast and took to hanging around near the water surface beside the filter, despite otherwise looking in perfect form - colours, fins, etc. I spent quite a bit of time with him, pleading with him to hold on, as I had a great life planned for them in another tank which they'd move into after a month. I left him be for a while and sadly he didn't make it.
I then wondered if the two espeis were stressing out the cardinals as they're very active and have been chasing one another up and down the wall of the tank in the filter outflow. I decided to set up a 3rd tank, using my spare equipment, with the intention of letting them swim off their initial energy in there, then hopefully all would be fine in a month's time on entry into the main tank and with the other rasboras for company - and giving the cardinals some peace in the 2nd tank before entry into the main tank and joining the others. This set-up rendered the spare room completely out-of-bounds, except a narrow area for me to get to reach the tanks. The palaver of trying to set up the 3rd filter (not yet used although I was convinced I had tested it out), divide the mature filter media across the 2nd and 3rd filters, then upturn the contents of a cupboard in an attempt to find a plug adaptor for the 3rd filter (the plug was 2-pronged rather than 3-pronged), transfer sand from the main tank into the 3rd tank (and realising I'd 'contaminated' tank equipment between quaranting and main tanks in the process), then get told off numerous times as fish-related equipment was strewn on the bed, in the corridor and living-room, and water spillages were galore due to filters being moved in and out of tanks! After all this, it has transpired that the 3rd filter, to be used in the 2nd tank while its filter has been transferred into the 3rd tank for the espeis, has completely calmed down the espeis... so now I'm contemplating dismantling the 3rd tank altogether and just putting the mature filter media from it into the 2nd tank.
Suffice to say that this accurately reflects proceedings in our household today:
FCMF:
and
Mr FCMF:
and "I think you should just get and keep a rubber duck as a pet - it would all be so much easier and less stressful all round".