I have the small version in a 36 gallon tank, it looks a little small, probably better for a 10 gallon tank. It is not heavy enough to stay in position with the air on, it does bu... view morebble nicely you just may have to weight it down.
I have the larger version in a 57 gallon tank. I think the dimension if great in this this tank, not too big not too small. The large one is also a bubble ornament with an air stone attached inside. The cave in this large one is a good size and my pleco uses it all the time for hiding.
Either size is a great addition to any tank for a Stargate fan! Match the size to you tank size. The small one would be good for about a 2 gallon to a 10 gallon. The larger one should be used for anything larger if you want it to be more than a small foreground accent piece. view less