What to put in an empty tank?

[Treebeard]

I have an empty 46 gallon bow front waiting for something to move in. Lighting is from a one bulb 36" cheapy fluorescent so corals are out of the question. I have an Eheim canister filter for filtration and about 20 pounds of live rock that is presently waiting in a 10 gallon tank. The live rock has aiptasia so I was thinking I would put it back in the 46 g. tank and add some sort of butterfly to clean it up and and eventually turn it into a sea horse tank.

Is this setup suitable for keeping sea horses?