Red Tail won't eat.

[Vypyrz]

I've never had this problem where my boa doesn't want to eat. He's usually really good and will take down a rat in less than 5 seconds.

I just started feeding him live large rats and on the third week i had to give him a small rat cause thats all that was available and the rat was in his tank for 1 whole day.

What should i do, or what should i be looking for?

Since you just increased his prey size and he is 2 years old, try putting him on a 10-14 day feeding schedule. He will need a little more time to digest the larger prey.