Re: IS SOMETHING WRONG WITH MY FISH?

To this day i don't know if fish sleep, so I can only tell you that they do 
rest sometimes and when they do they don't move much.  I suspect your black 
fish is sick and you should probably consult the pet store who sold it to 
you or at least talk to them about different treatent options.  Without 
more information I cannot tell specifically might be wrong with your fish.  
On the other hond, it might just be adjusting to its new environment, but 
that should only take a couple of hours.  If your fish doesn't start acting 
like the other one soon, talk to your pet store.