I've kept my fish in the dark for a week at times and I can tell that they
can tell the difference. I'm not sure if it harms them though. I dont think
anyone can answer that question. I know that certain fish lose their colors
when they are in the dark.

"Mickey" wrote in message
...
I read an article that said fish do not care about lighting. So when I
moved
my fish into the dark basement I made no lighting provisions. Any past
experience on fish and lighting ? The indoor pond is 4' x 4' x 3 deep 300
gallons. The water temp will be about 72° all winter. I am looking at a
cover to reduce humidity loss and hold heat in. I thought about putting a
light though the top and hanging it so the base is outside the cover and
the
body is inside. This would provide some heat and lighting.