Electric blue dempseys

I picked up some electric blue dempseys at Big Al's (Mississauga) recently
and wuz wondering if there wuz some info on these guys on the net. I've
done some searches on them but I've seen nothing so far that describes these
fish. BAsically mine are half an inch each...a bight light blue with dark
spots. Fantastic looking fish (and expensive too at 3 for $60 cdn). Does
anyone out there have experience with these fish?? I've been told they are
related to the jack depmsey cichlid but they are a more mellow variety (wuz
told it wuz safe at this size to put into my planted tank with my many
cardinal tetras).

How fast do these suckers grow??
Willl they maintain their color??
Will I need to separate them from my cardinal tetras eventually??
Any websites with more info on them??

Any help would be appreciated.

Dave