some fish get stressed out more than others, alot of fish can change there colours depending on there mood. and it is possible that you bought a sick fish (doesnt hurt to take it back and get a new one)
also if there brand new then they'll hum for the 1st week or so, i bought 2 of the 103'fs for my 450L tank and there pretty silent now, and the flow slows down a tiny bit when there worn in so dont be put off by the strong current at first