Mine really like nightcrawlers - I cut them into 3 cm segments for them and rinse them well to get rid of the slime. If you place a piece in front of the salamander's hiding place or inside, you can see next day if it's been eaten (tail and head parts can crawl away and hide, so it only works with middle parts). Mine will also sometimes take crickets from tweezers. They should be small and dusted with vitamins. I would personally not recommend waxworms. One of my animals got impacted from them and nearly died. If you do want to offer those, make sure you pierce their skin several times.