Neutering is not going to help - training is. But a good trainer will train YOU to deal with the dog. If a trainer can get him to behave but you can't - there is little to be gained from paying out money. This is something you should never have allowed to happen, but since it has, I think you should deal with it and @JENGOSMonkey has given you a good idea to start you off. Withdrawing treats is a good idea, but also, get up and walk away. He could be biting to get attention and therefore you withdraw the attention at the first sign of a bite, with a firm NO.
Fence fighting & redirected aggression
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My 7 yr. old B, Rocket, is a fence fighter. At home with the 2 shih tzu's next door he will race up and down the fence, hair raised, and attack the fence. If my female, Rumor, is helping, he will turn and snark at her too. At daycare, he bit one of the helpers when they were bringing a dog in. It is always when he is at the fenceline or on a leash that this occurs. What do I do when this happens?