My adult male beardie lives in a 40 gallon breeder tank. It is furnished with lots of things for him to do. Thick branches, etc. And a half cinder block under his heat lamp for a nice basking spot.

He is 2 years old and about 16-20 inches, I haven't measured him.

For the past year he has gone through phases of freaking out in his cage. He brumated for the first time a couple months ago, and since he's been awake he is almost constantly clawing at the sides of his cage and trying to scale the sides. He also does head bob and puff up a lot since coming out of brumation.

Is a 40 gallon breeder enough space. I don't want to buy a 55 gallon if he's still going to freak out in it. But I guess I wouldn't know until I tried...