If Tank is snapping at other dogs, then he's not enjoying their company. I'm probably right when I'm guessing the owners of the other dogs don't appreciate it very much. Puppies are impressionable, so you don't want them to experience this kind of thing either. Keep him away from dogs he doesn't like. Don't take him to dog parks. Why is it important to you that he plays with other dogs? I know dogs parks can be fun places, but not when you're the person with the biting dog!