I think the biggest question I'd have if I decided to go this route would be how many lights are necessary for adequate coverage without any poorly lit spots.
I mean looking at this pic:
Originally Posted by m00se
...well, just looking at the size of the tank would make me think that 2 fixtures might provide enough light.
Trial and error is likely necessary... in any event, the whole project is low cost, and probably fun at the same time.