I actually just set up a 20 gallon tank to house 2 frogs. I bought: Tile Runners/Holders from Home Depot (they look a lot like the clips that you bind your school reports in, only these are much longer and easily cut), Acrylic sheeting from Home Depot, and Hot Glue. After cutting the acrylic to size (easier said than done), I bordered it with the runners, cut those to size, put it in the tank, and hot glued it in place. Some people use aquarium silicone, but with my tiny apartment, the hot glue was easier. If I need to clean I can slide the acrylic sheeting out of the runners for easier access. Because the acrylic is clear I've had to put contact paper/ aquarium contact paper on it so the frogs can't see each other, but it's worked wonderfully so far!