You might need to order one if you can find someone who'll make them as they might take a few weeks to build. Best off constructing the viv and letting it sit first for a few weeks before getting the frogs just so the plants can grow and make sure everything's alright. By small I mean like a 20 gal cube but that Exo Terra tank you have is like 50 gallon or something. I'm going to be using a spare 18 x 18 x 18" exo terra for my first darts being 2-3 leucs but will have to do a few adjustments as mentioned.