Try some different things. Dont be afraid of trying some fresh fish clams oysters. When I had tranny I tryed lots of things. Tranny liked some and not others but I feel changing up the food is good for them. I would feed until he wont eat anymore. More the better but of course dont leave uneaten food in the tank. I know we use table shrimp for the most part but I found that I could get live bait shrimp and A LFS that sold slipper lobster. Check out and see if you have any bait shops and also what does you LFS sell.