My bearded dragon (Skecher) is growing so quick...he/she was the size of my finger when I adopted him/her in December. Skecher is now about 5-6 inches snout to vent!!! I thought I would have until the end of the summer to get a new tank. He/she is in a 10 gallon tank now. I really think Skecher needs a bigger tank soon. What size would you all suggest? 40 or 50 gallon? And Exo Terra makes one I really like, and not sure about the 2 sizes...36x18x18 and 36x18x12.