I have a 55 gallon and a 75 gallon tank that I am trying to find new homes for. A friend of mine asked what kind of herp can live in these. I have a solid piece of acrylic for a divider for the 75 to give him if that's the one he wants.
I suggested a bearded dragon which is what I had living in the 55 for 10+ years, but he's interested in something "a little more exotic" than that. He's a smart guy and takes good care of his own but I'm unsure that he's ever had a herp before. I got the impression that he did tho... not sure... But he said he wanted to do research on whatever he can keep in there before getting it (whatever it turns out to be).
a 75 gallon would be ok for awhile, but they will need a much larger cage when they are an adult:
Water Dragons need a space at least 2 x their total length therefore you will need to provide an enclosure that is a min. of 6 ft long (side to side), 2-3 feet deep and 4-6 feet high to do it right
I have a 75g tank myself that I plan to set up as a display for a false water cobra one day. But I certainly would NOT recommend one of those for a first-timer though.
The 55g would make a fantastic dart frog setup! Or a small (2-3) collony of crested geckos would be nice in that too.
A rainbow boa would be great for the 75g. Also a rough green vine snake would make a nice display.
How about a blue tongue skink? They have about the same care as bearded dragons, but look a little more exotic. One could fit in either the 55 or the 75 gallon tank.