iv noticed that my common bns sometimes go from there grey brown color to almost calico like in coloration then go back to normal. is this stress? should i be worried? normal?

this is mainly normal mate.....
Its a sign of stress and could be caused by lots of things...
ie. two male's will change colour if they are close to each other and ready for a scrap..
also feeding time is a big colour changer especially were female's are concerned..

This is perfectly normal.......

The only time to worry with a BN's colour is when they go all one colour like grey...and stay that colour , then you can worry....

With albino Bn's they will tend to go from yellow/white to a pinkish reddish colour with a dark red patch on thier fore head when stressed........

Hope this help's mate......

my female does this too she can be yellowish then greyish then brown to dark brown ive noticed certain areas of the tank relate to what colour she is shes always yellowish on the light coloured rock side which has more natural light ..shes dark brown by the darkest side of tank where filter is and goes greyish mid tank you can see her colour alter as she gets a dark mouth ..
shes always different colour in mornings too ..

maybe she thinks shes a neon or a chamelion lol ..

cant be stress i feed and look after her kids and tidy her home whats she gotta be stress at lol xx

Just being nosey - what;s wrong with a grey one?

well it can mean internal parasites ive not heard many poeple with a sucess story when they've had an all grey plec...

Lars does it all the time lol. When the lights first come on, when one of the others gets too close, when I suddenly appear and gawk at them etc haha
Just them getting pissy