Tubs work great for horned frogs, also. I have mine in a tub that's roughly the size of 2 shoebox tubs. It retains humidity like a dream (something that's tough in tanks.) I like to keep my frog's humidity pretty high, otherwise she tends to dry out and develop a hard clear outer skin (they do this while "brumating" in the dry season in Argentina, their homeland.) A rock on the lid and some airholes melted into the sides, and you're good to go. I fill it about 2/3 full with substrate; these frogs LIVE to dig.