About a week or so ago I bought 2 small (about 1 to 1 1/4") Hongi. In the lfs, which carries quality fish, in the plastic bag while bringing them home, and when I first put them in the tank they were of the bluish color with red dorsal. For some reason or other they have taken on a much darker color and I have a tough time telling them apart from my rustys. Cou;d this be "normal"?