Re: help fish upside down
 

something here if your fish decides to have a "lie down":D

http://www.provet.co.uk/fish/fishswim.htm

Re: help fish upside down
 

as some one said above swimbladder

dunno what the thing is but its something to do with digestion

there's some stuff called melafix that shops sell - its paracetamol/anadin/laxative all in one for fish - its magic stuff. put in a dash of that if it does it again. its like an infection swimbladder is and this cures it