Hello and welcome!
I would personally suggest filling that enclosure with some plants. I feel it may be a little bare for him in there. Also, I saw you mentioned you're using a T5 bulb. That's good, but it's hard to tell how far away that bulb (and the basking bulb) are from where your chameleon can bask.
I highly suggest you head on over to chameleonacademy.com, and review all of the care information there. It gives graphs and info on how far you want your chameleon to be from those bulbs.
If he's too far away, he's not getting enough UVB/heat. Too close, and and he's getting burnt and possible damage to his eyes. Please pay attention to the details, as a 6% / 5.0 UVB bulb, will have different distance needs than a 12% / 10.0 uvb bulb.
The enclosure also looks on the small side (hard to tell from the pic), so you may want to compare that to the recommended minimum (2'x2'x4'), and possibly look into getting him a bigger enclosure sooner than later. Good luck with him! You landed at the right place to get help for sure. This place is loaded with nice people who have a lot of experience and can definitely help.