Normal amount to feed a growing axolotl?

[hunterwho]

I got my axolotl a few months ago, and he's been thin ever since I got him. I've been feeding him little bits of earthworm every day, but I don't think I'm feeding him enough. However, he doesn't react to food that just sits in his tank; he has to be specifically fed live pieces, and I have to space feedings out because he won't snap at food again right after he's just eaten. My question is, how much should he be eating every day? Is a whole earthworm cut up into eight or ten pieces and spaced out too much, and will he stop wanting to eat food once he's had enough for the day?