That's a good sign if you are seeing him eat the worms that you are feeding the cowfish. It means that he knows there are other sources of food. if you are adding a bag of live pods
it is a good idea to add them after lights out so they have a chance to disperse, and establish themselves.
I know with my tank when I first turn my lights on I can see pods
all over the glass. My toby detaches himself from his rock sleeping spot when the lights come on and has himself a little breakfast before they all disappear back into the sand and rocks. I only have about 30 pounds of rock in my tank, and most of that was dry rock when I put it in. So, the pods
that are in there all came from about 10 pounds of rock.