agree with TC ... dats learn how the other dats eat and will go after what the others are eating once he is hungry .. it might take a couple of weeks before he will learn that frozen shrimp is food .. if 3 weeks pass and he's still not eating, I'd quarantine him and feed him live again but give him a 1/3 amount live shrimp than what you normally feed him every other day for about 2-3 feedings .. during this time, feed only one live shrimp at the time until fully eaten
at the 4th feeding, put some live shrimp to sleep in the freezer, take them out and start throwing one dead one at the time in the tank. He should take these dead shrimp by now. Continue for two or 3 feedings of dead shrimp. After which, switch to frozen shrimp. Cut them up the same size as the dead shrimp. This works everytime. Good luck and let us know progress.