Extremely agressive Bearded Dragon - help?

[kameo37]

Could be lots of things. Your husbandry needs some correction and that could definitely be it. Even if you have had him all this time with no problems, they can only stand so much and then the dam breaks...which can show up as aggression. I will try to help!

Cage size: for his length he needs a 4x2x2 (or 18 inches).
Substrate: get him off of that sand immediately! When did he poop last? One of the signs of impaction is aggression. Replace with paper towels, tile (my fave), repticarpet. No loose substrate with these guys.
Diet: no mice. No lettuce. No celery. They need dark leaf greens (collard, mustard, bok choy, dandelion), butternut squash, summer squash, etc.
Lighting: one white basking light and a uvb (reptisun 10.0 tube or arcadia...1/2 to 3/4 the length of the enclosure). No colored lights at all. If it gets below 65 F in your house at night, you should use a CHE for additional heat. If not, just turn off the lights at night.
Temps: You need to measure temp of basking area, and ambient temps. They need a heat gradient of 75-95 (for an adult) with 95 being the basking site.
Baths: You didn't mention this part, but he needs baths. If he is impacted, I would give him one everyday. On a regular basis, at least twice a week.

If he is impacted from the sand, you can give him a few drops of olive oil from a syringe.

My last bit of advice: www.beardeddragon.org

I know it seems like a lot. Everyone makes mistakes. These are easily corrected and you can get him on the right track! I'd love to hear about his progress after his husbandry problems are fixed!