Yes fish will eat earthworms. Try to use small worms. If you have big earthworms, you need to cut them up and that is really gross because they produce mucous when stressed and it becomes a slimy gooey wriggly wormy mess that's hard to clean up. So small worms only and use them whole.
Get a few different types of frozen food like brineshrimp and bloodworm. And visit a fishing store and look in their bait freezer or the seafood section at a supermarket and buy some frozen prawn and fish. Keep it frozen and take a bit out each day or every couple of days, defrost it and cut it up for the fish to eat.
If you have live shrimp in the tank, use cooked prawn so no diseases can get in the tank from the frozen prawn.
When feeding prawn, take one out and defrost it. Remove the head, shell and gut (thin black tube in body) and throw these bits away. Use a pair of scissors to cut the remaining prawn tail into little pieces and offer a few bits at a time. Feed until the fish is full then remove uneaten food. All the fish can eat this, not just the catfish.
Feed a variety of food so the fish doesn't become reliant on one type of food.
