Well done on the rescue!! <3 I'm thrilled Crazy will have friends and that you were able to save someone. I adopted 3 pond rescues almost 6 years ago and I know how challenging and rewarding it can be. My rescues were terrified of me. They ran to the farthest corners of their aviary when they saw me coming. Now they run or, "fly," to my feet quacking with excitement when they see me coming.
I agree that mealworms are your friend. If he won't eat them dry, perhaps try floating them in his water. He may not recognize the dry hollow texture as food. He also may be too anxious to eat when you are watching. If he eats mealworms wet you might be able to get him to eat them dry and crunchy after a couple weeks. Then you can top other foods you want him to eat with mealworms. This might not work for your duck, but it did for mine.
I have also had to tube feed. It can be challenging, but not too bad after you become accustomed to doing it. After a couple weeks I could even do it myself.
You are doing a great job.
I agree that mealworms are your friend. If he won't eat them dry, perhaps try floating them in his water. He may not recognize the dry hollow texture as food. He also may be too anxious to eat when you are watching. If he eats mealworms wet you might be able to get him to eat them dry and crunchy after a couple weeks. Then you can top other foods you want him to eat with mealworms. This might not work for your duck, but it did for mine.
I have also had to tube feed. It can be challenging, but not too bad after you become accustomed to doing it. After a couple weeks I could even do it myself.
You are doing a great job.