Hmmm, if they dont have any sign of disease (skin, flashing on objects, feces white, skin damages) i would say that they are unrestless, because they are in a visual shock. They are in the tank which is whole balck and they experience void withot shelter. Dark water (dark sides) could harbour predators and they are desperatelly looking for a shelter to hide from them. Beside that they are albinos which react even more intense on the change of light conditions.