Hey
I have a vivarium for my Syrian.
There were plastic vents in the lower and upper corners. I changed them to metal to prevent chewing and escaping. I got these off amazin and they cost less than £3 each. We also cut a large hole across the top of the tank and then placed wire mesh over the top for extra ventilation. Got from local hardware shop for about £7. Works a treat.
Here are the vents. They were the size of our holes:
https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1
The 2 vents we had didn't feel like enough ventilation. So that's why we added the mesh on the top also.
I also purchased a small rubber wedge for the glass door just incase to ensure the door can't be opened on its own. It cost 99p off ebay.
Hope this helps ��