I have had good success by going a day or two without offering food. Let him get hungry, used to the new environment and stop freaking him out by shoving stuff in his face
. Then try thawed rinsed fresh shrimp (if you can get them whole and unshelled you will be better off) on a clear plastic feeding stick - wiggle it near a rock or on the bottom as if it is alive. Be patient. If the shrimp doesn't have eyes, sometimes drawing eye spots on the shrimp will induce a strike.
If there are fish in the tank, you may want to take them out as they may be frightening the cuttle.
You might have to get something live for him to eat if you cant get him to take dead food. WC cuttles are often difficult, if not impossible, to get weaned onto frozen foods.
The store near you must have some kind of live shrimp or crab you could feed if he isn't going to eat dead food. You may have to order some live food to keep him alive until you, hopefully, get him weaned. If you do order, you can try to feed him freshly dead shrimp which may help weanin him.
I haven't really tried to get them to eat frozen foods from the grocery because they don't seem to eat as much of them and IME, they don't do as well on them.
Oh- they don't eat clams.