i have had the same problem in the past. my lfs
has a tank for blue legs, but they are not all blue. they look exactly the same as blue lags just with brown and gray colors instead of blue. they do exactly the same thing tho mine hasnt done anything out of the ordinary, i think i have two or three of them, the only thing i have noticed is that one has grown a little faster than the others. all in all, i wouldnt worry about them.