Adult axolotl won’t eat worms anymore

Hello. I’ve had my axolotl, Kevin, for about a year now. I took him in from a family that could no longer care for him. According to them they fed him worms from their back yard. When I got him I tried feeding him both store bought earth worms and axolotl pellets. He only ate the worms and never pellets. He has occasionally been a picky eater but usually all I have to do is pick a new worm and blanch it. In the past 2 weeks he has now refused to eat worms no matter what I do. I have tried blanching them, cutting them really small, offering multiple worms. I started to think he was sick because he wouldn’t eat so I tubbed him and checked all my water parameters which all came back normal which no big changes. I offered him blood worms which I often do as a snack which he ate. I then offered him the pellets pictured above on a whim thinking he wouldn’t eat them because he never would before. Well he did eat them but the problem was he will only eat them if I hand feed them to him one by one. I have tried teaching him how to eat off a plate or go inside a cup and eat them but nope. So I have a few questions. 1. Are these pellets a suitable diet for him if he never wants worms again? ( I know earth worms are the best diet overall but I can’t force feed him) 2. How many pellets should I feed him? (They are about the size of a tic tac) 3. How can I get him to eat worms again? Thanks for any advice.