I have seen "submersible flourescent lights" on several websites. They come in Blue, green, red, etc. I guess they go down in the sand/ cc.
http://cgi.ebay.com/New-Odyssea-Aquarium-Submersible-T5-Light-13-Blue_W0QQitemZ7725769092QQcategoryZ46314QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
I think it...