He's also 'VERY' hissy lately, he doesn't hiss much, or never has i should say until this whole not eating issue came up.
Hissing plus not eating could be a sign of husbandry issue I know you said that your husbandry was perfect but what type of set-up do you have?

How big is your enclosure?
What are your exact temps and humidity?
What type of thermometer/hygrometer do you use (digital,dial,stick?)
How are your hides? (dark, tight, identical?) could you describe them?
His your enclosure in a low traffic area?
How often do you handle your BP?