What can go under this?

[justinl]

forgive me for being presumptuous, but the fact that she chose a 3 inch wide tank tells me that she (let alone her system!) is NOT ready to keep seahorses. IMO no fish bigger and more active than clown goby could ever be housed in those kind of dimensions. Definitely no fish (or any other organism) that needs to sift sand for food. I do like the pistol goby pair idea if you stick to one of the hardy smaller species of gobies and it can survive easily on prepared foods.

ledges will be anything from hard to impossible to create... you're basically working 2D. You could do 2D ledges (in profile) by using magnets to stick rocks midwater, sandwiched between the front/back panes of glass... but it could make maintenance a real PITA. IMO you could get away with zoas, shrooms, and other smallish polyp softies... I wouldn't recommend leathers and other such large stalked colonies since the stalk will grow onto the glass from the rock and generally, big white blobs that may obstruct the view of the corals polyps don't appeal most people. GSP could be nice i think.