Wow, you brought an aquarium from germany? That seems like one of those things where you would be better off just getting anything for it there and then buying new when you get home.
I think you could actually use the 220v equipment unless there is a problem running their 50hz equip on our 60hz AC voltage.
Might be worth looking into.
I don't know off hand of any good canopy threads but you would probably need to be more specific like... what look are you going for? Do you want to have a stained wood outer skin or a black painted look or anything else...
Are you wanting to use T5 lights, VHO, PC, MH etc...
I know someone who made a shelf and mounted it to the wall then mounted their pendants off of it and there is a nice place to display photos and thing above the lights now.
Whatever you decide, good luck with it.
-- itZme