well thanks for hte advice guys sadly he didn't make it. It's a shame it was a really nice looking one too. my gf's favourite fish also...
Luckily I should be able to get another one. I don't necasarily think it was a problem with oxygen because all my other fish are perfectly healthy and acting normal. I found him by the side of the tank (where I assumed he slammed into) virtually lifeless upside down and twitching. thats why I think he probably knocked himself out. He was literally paralysed when I tried to revive him in the net. Still breathing but unable to move.
I had the same condition on a convict a few months ago that got shocked by an electric catfish I kept. the fish was paralysed and could only swim on his side like a flounder, I had to put this guy to sleep.
Either way thanks for helping guys, its a real shame to see this fish go. I wonder if there are any other alternatives for an active top dweller in a 5x3 footprint