I recently swapped tanks with my mothers, She took my 125L tank and I got her 240L tank pictured above.
It was a busy 7 hour task, to get them drained moved and refilled. See also only lived down the road so it was mostly all spend on draining and not transport.
Image above is the setup I have now, however unfortunately I've had some trouble.
3 of my fish have become ill.
One died yesterday, It was my first fish who had been with me for 4 years. It was an Oranda and it had been through a LOT, It suffered and survived my early mistakes in fishkeeping, survived various illnesses. But this time was too much and it died.
My other two are now in isolation, being treated with esha 2000 in a highly oxygenated tank to give them the best chance of surviving. Hopefully they pull through, though one is particularly worse than the other.
I had done some investigations to figure out what I did wrong. Was it the tank move? Did I nuke my cycle? Did my water get an ammonia spike?
The answer too theses is NO. I did nothing wrong, My water params are perfect, My filter is untouched and still fully cycled. I don't know what happened but I'm thinking it was a preexisting thing that had gone unnoticed and had finally reached a critical point.
All I can do is monitor and treat and hope for the best.