Boa will not eat and is aggressive

Question
Hello again,
I asked a question a few months ago and your answer was very helpful.  I come to you again regarding some new issues.  Our red-tail boa has not eaten in 2 months now.  We tried feeding him a month ago.....he killed the rat but never ate it.  

He just had a very successful shed a few days ago, so I know the temperature/cage conditions are not the issue.  We tried feeding him again the day after he shed and he just got angry.  He wouldn't even strike at the rat but he was just hissing up a storm when it was walking around the cage and even walking on him.  Also, whenever he senses movement, like when we walk by the tank or come to check on him he hisses.  I reached in and started petting his mid-section and he hissed real loud, and he tensed up off the ground.  I've done a ton of research on different infections and illnesses and nothing seems to fit.  Any help would be great!  Thanks!

Answer
Depending on the size of the boa, 2 months is not a long time. It sounds like you are up to speed on infections etc., so I am indeed guessing this is not the issue. I have a couple of snakes that do not eat well in winter. I am not sure why, but they eat about once every month or two and pig out in the summer. What I advise you to do is to keep trying. Feed at different times of the day, try a hamster or quail. If you usually feed rats, try mice. If you usually feed white in color, find a dealer that sells black and white. All of these little things make a difference. Once he eats the first time, he will likely go back to a normal schedule. Make sure he has plenty of water and take him to the vet if he does not show signs of improvement in the next month.