If you can get him eating live fine, try starting with that, then feeding him a f/t directly after he finishs the live one. There's usually a feeding response right after swallowing a meal that will be enough to induce a 'less desireable meal' to be acceptable. Getting a taste for the f/t might be enough to get him to eat it in the future. For now he doesn't associate it as food. Remember to wiggle the f/t!