Hognose wont eat

[acidonangles]

Okay so I keep him in a 20 gallon tank. I have a normal bulb for light set on a timer of 6:30am to 7pm. I have a heat pad that is around 85. The other side is 70. I am getting a heat lamp to heat the tank some more. I have 2 hides 2 plants and 1 water bowl almost in the middle of the tank but closer to the cool side. He is super active and goes around the tank constantly and tries to climb the walls, that or he's sleeping.
I went to an expo almost 3 weeks ago and got Nero, my snake. They said he has eaten 3 times and x-small pinkies. I let him settle in for a week and tried to just wiggle it in front of him. All he did was hiss once then tried to escape and go the other direction. So I left it in with him and dimmed the lights for an hour. The next time I tried salmon juice of the head of the pinkie, same thing happened so I left it and Nero in a 5.5 quart tube and he didn't eat it.
This Wednesday I am going to try and brain the mouse before feeding.
Any suggestions? What weight should he be? He's about 9 inches.