Hi.

I've fed my boys small slugs before - they love them and snatch them up (only Louis has troubles once in a while, but he's notoriously bad at snatching earthworms, slugs - anything not a bug lol). So slugs can do just not too big. When I feed my two guys earthworms, I pick them up, place them on our floor (wood) and they then stalk the earthworms, until caught. This is easier for me, since the earthworms quickly burrow, if I let them loose in the tank, and they guys get bits of dirt in their mouth when snatching them, which makes them spit it out and not wanting to take the worm. (we never use any chemicals to clean our floor).

Otherwise, they are fed slugs from my finger or tropical bench chunks or crickets in a bowl, in the tank.