The fish oil is probably going to be your best bet.

Put food out and wait by it, but not where you are too close. If he comes regularly, sit a little closer each time until you practically have the food in your lap. Let him get used to you. If you just grab for him, he will mistrust humans for the rest of his life. Mind you, some of the sickos there are in the world, that's no bad thing.

LTS