Would a 2x4 180 gallon stock tank be a good enclosure for an adult bearded dragon? I'm looking for a cheap but large option for an enclosure, as my bearded dragon could probably use more space. I've seen it done with a Savannah monitor before.
Also! Would a smaller stock tank work? I want her to have the space she needs, but I want to know if a smaller size would be good.
Space wise it should work. You could suspend lighting overhead using adjustable stands. I've never seen someone use one as an enclosure though. It won't hold heat as well as a wooden enclosure. The opaque sides might feel oppressive to them since they tend to be really curious and like to look at their surroundings (put a dragon in a window sill and they'll look outside for hours). Maybe a modified version with some plastic or mesh installed on the sides would work. In the long run you're probably better off building a more traditional style enclosure though.