Check with the pet stores, they have colored 'mini' lights for accents, that might give the effect you want.
Also, if you can, switch your main lighting to fluorescent if it isn't already. They give off less heat, use way less power, and last a lot longer than incandescent. They come in a few colors, too, including a blue 'night' color.yes you can but only if you have a live plants will i'v don it and i don't recommend you with that coz it will be very dim and your fish wont be clear to see!!!!!!i myself once in a while change the light bulb to a different color
i have only seen them in blue, green and red so far
i have used all 3 of them at one point
the blue one, gives the tank a very nice tint, but is very dark
the red one, gives it a red tint, but you can see the fish better
the green one, well that one is the darkest one, and i could hardly see my fish at all
it's all a personal preferencedepends on your brand of tank.
if you have a regular rectangular tank you can get a vast aray of different tank lights, this one is a new LED lighting system:
http://www.aquatics-online.co.uk/catalog鈥?/a>
There are also these pod LED lights available in various colours:
http://www.pets2home.co.uk/item--MARINA-鈥?/a>
I wouldn't recommend black light long term as it can stress out the fish.