Rehoming our beloved dog (Ventura, CA)

This is painful and sad to write but our 7 year old Saint Bernard Pit mix bit our 2 year old child so we have to rehome him.
Our dog was provoked by the 2 year old hitting him so it wasn't random and luckily the bite was very minor but still we can't have him living around our kids anymore.
He's truly an incredible dog and we love him so dearly and I know at the right home (without kids) he would be very loved and make someone very happy as he's given us so much joy the past 7 years.
His name is Fish.
He's an amazing alert dog that barks at the sound of anyone approaching the house.
He made our family feel very safe over the years.
And he's very very sweet and loving.
He does mostly great around other dogs but sometimes feels a bit threatened by unneutered males that are in his territory (outside of the house it's a non-issue).
He himself is neutered.
He truly is a special kind intelligent dog and it really pains us to have to do this.
I just pray we can find a loving home for him.