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he will let us pet him, but everytime we try to hold him, he bites, all the time, for no reason,
There is a reason. They are a prey animal and are scared to be held. By biting, it probably resulted in him being released which was the aim. Now he would know that is the quickest way to escape. Completely normal and common for our rabbits. They are not hold and cuddle pets. You may know of someone with rabbits where this is not the case. Most rabbits dislike being held. Many rabbits learn to tolerate it to a degree. A minority may actually enjoy it. Absolutely spend time down at his level on the floor. If they have a 4 paws on the ground they feel more secure and may even stay for a floor snuggle.
At the fair he was likely handled alot. May even have been too petrified to react (?) Was he a baby? Baby rabbits are ok with being held, especially if the breeder has done this from a young age, socialised them. But they grow out of that baby stage. As mature rabbits, the truth is the times of those long periods of been held are over.
Avoid picking him up. Allow him to come and go on his own terms and eventually he will build some trust. Also, as mentioned, look at getting him neutered if he hasn’t been. This can also help with unwanted behaviours.
I hope you’ve had a chance to browse the site. There is a ton of useful information and lots of members wanting to help make things better for you and your rabbit.