You can make feeding more of a game (if you just normally drop the food in). Use some good sized krill or other larger sized meaty foods and dangle it in the water. If he comes right away move it away a little and make him chase after it a little like he would in nature. If he is a little skiddish try moving your hand slowly closer to him. He might braven up and take it right from your hand or he might dart away. If he darts away then try moving towards him again and right before you get to about the distance you got to him before, let the food go and this I would think would teach him to associate your hand with food. Soon he should braven up when he realizes your hand is nothing to fear and then maybe you can try doing the chase game mentioned above, just something to keep it's wild instincts in tune and get a little exercise
he may also think that my hand is food lol
i tried what you suggested about the chase game, i used a worm, he chased for a while, then i thought it was a little nasty of me, he kept on looking at me with those big red beady eyes so i gave in

, he loves his worms