The shaking is called the "clown twitch". It is the clowns way of being submissive to the other one. Completely normal behavior and nothing to be worried about. I would also not worry about it hiding in the torch like that. Looks like it's hosting it to me Also completely normal. They both may dive in once they become bonded Just keep with the food suggestions and let them be. They will figure it out. This is simply something all clowns go through during the pairing process.