Well, it's been quite a morning. Coming to the conclusion that I am nothing short of a total muppet has been quite enlightening. I am far from happy with what I have done, but decided to share the story in the hope that others could learn from my mistakes, and in the hope that others would also document some of their errors (if any) to make me feel a bit better.
A few weeks ago I replanted my tropical 125L tank with real plants. The aquabase went in, followed by a substantial amount of substrate. Everything went well and the glass bloodfin tetras settled back in, then I got some silver hatchets and a little bristlenose plec. All was good. I spent a bit of time on the CC to look at stock levels, then had a good look at the tank. I had gone a tad overboard with the substrate and realised that if I had not used quite so much I would have more space available. Last night I moved the fish, heater and filter to the temporary tank and moved the majority of the plants to the plant tank.
The plan for this morning was to remove the water and some of the substrate, then start again.This is where it went very wrong.
As I was removing the water I thought I saw some movement. I thought perhaps it was bits of dead plant, but on closer inspection it turned out to be a lone glass bloodfin who had been in the tank all night without a filter or heater.
I had thought I was capable of counting to eight, but apparently not. It has been moved to the temporary tank with the others, but I am very concerned that my actions have caused it a lot of distress and that it's chances of survival are not what they should be.
I have continued with my tank plan, removed most of the water and an entire bucket of substrate, and have started to refill the tank. I'm going to replant, but leave the fish in the temporary tank for a few days because they've been through enough for now.
When I do move the fish back into the 125L tank, if there are any fatalities I will know that I have made a huge mistake this week with my fish. I'll be keeping my fingers crossed for the health of my fish, and have learned a big lesson about planning tanks, but could still kick myself for my stupidity.