Cal king won't eat.

[KingOriax]

He's 2 years old and was fed on live mice before I received him. I got him a little over a year ago and have slowely brought him to to frozen adult mice. He is 3 feet long and has not had any issues feeding since the first few weeks I had him where he wouldn't eat. I will take some pictures in a bit and include them but the tank is 40 gallons, has a hide on both sides, one side has an under tank heater and a heat lamp, and the bedding is aspen. He hasn't eaten in over a month and i'm starting to worry, today I tried a fuzzy just to see if he would eat something small and he backed away like it was a threat to him. Any advice would be appreciated.