I seemed to notice on my other clown when he was still with us, that his eyes sort of diluted a bit, his pupils got smaller (if they have pupils??). Could have been imagining it though!
At the moment, I THINK my remaining clown is going brown, it may be due to the lighting in my tank being too low though - if I upgrade the lighting, and the colour it is just down to that, will his orangey colour come back? He's currently in the bottom corner, bobbing up and down on the same spot, facing upwards. He usually sleeps like this though... Breathing seems to be normal though, he quite often goes for a bit of a swim, and he's eating like a pig! :p
My 3 shrimps don't seem as active as they were - mostly stay on the same spot, or wander round every now and again. Unless I put some food in! And then they all go MAD! Crawling up the sides, or skimming around on the surface, jumping, etc!! Quite funny really
Water quality is still "perfect" (touch wood)... And my new powerhead is now directed at the surface, so it's breaking up a lot of the "scum", hopefully helping oxygenation.