Fish and LEGO(s)? Fishspace
Greg Towndrow has taken to Indiegogo to try and raise funds for a project called Fishspace - a product that would let you attach LEGO bricks underneath, inside and on top of a fish tank. It will be a one piece, injection molded unit, that's approximately 2 gallons in volume.
There are several contribution level perks (of course getting an actual Fishspace is included in there). Greg is looking to raise $50,000 by Thursday November 29th 2012 at 11:59PM PT. If that goal isn't met, the campaign won't receive the funds. The planned release date is in March 2013.