They are pretty much "not picky" so long as you give them space. You can house them together if they are about the same size. I have 4 juveniles and they are together. I made an elevated "dry" side, but I've only seen one frog ever go there. They mostly just hide in the water. I need to redo the tank as the dry side is collapsing, so even though I just changed out their water, it looks almost black. It's dirt from the dry side, but I think they prefer the murk lol.

They are messy though. They eat a lot (so lots of poo) and shed frequently. Looks like plastic wrap floating around in the tank. Definitely use a filter for them.