i learned last night that a fish can be knocked out.
i was turning out lights as i was about to watch a movie and the tv went black as i turned the last light off.
the fish got frightened and crashed into the tank and one red empress managed to jump 100mm out of the water through the triangle cut out of the brace in the corner (mostly blocked by fx5 outlet) and fall 1600 to the tiled floor below,
i quickly picked it up and put it back in the tank, unfortunately it sank and was gonna become a snack for everyone else so i scooped it out and put it in a 100mm cube and put a air hose in it.
5 min later and still upside down and only a little bit of movement so i gave up waiting and went to start the movie.
came back another 5 mins later to check on him and he had escaped that tank too, luckily it was on the main tank and he made it in there. all 8 of my empress are swimming around in the tank happily this morning.
morale of the story is dont give up on a sunkin fish as it may be out cold