Come out this morning and the girls say "good morning murray" then Miss A says "silly Murray what are you doing" so i get down to look at him and he's on his side

Have moved him to the big tank with the air cord and propped him against a plant, he's still breathing and get some energy, swims off then tries to right himself so when i see him not balancing i prop him up against the plant again and let him rest.
He seems to be trying to balance himself out a lot more so HOPEFULLY he pulls through, girls are devestated.

Not sure what could be wrong, he has fresh water, we've not over fed him and he was in the tank alone, the only thing we didn't have was an air rock.
I need to get a new PH tester but we don't do it with our other fish as they get tank water with no yucky additives and they seem fine, we didn't have a heater in the tank as the lady said he doesn't need it.

I feel horrible for poor Murray - the girls love him already & DP and i have always wanted a cod for a pet

ETA - the lovely lady we got him off called this morning (after i sent her a sorry for bothering you text) and we currently have him in a shallow tank with the air cord and a bit of salt - hopefully some highly oxygenated water and salt 9which helps with stress) will be good for him and we might just save him... he is still breathing so i guess we wait and see.

DD1 is sitting at his tank side and singing happy fishy songs to him, she's quite upset at the thought of him dying.. so i'm being good mum and am on constant fish watch

Come on MURRAY we need you to pull through.