i accidently fed my salvini one once, it was about half an inch long and he was about 6 inches long.
i dropped it into his tank for some algae control, but my salvini gobbled it rightup, it didnt cause him any harm, and he seemed to enjoy it, but i wouldnt want to make a habit of it. it sounded really crunchy, like someone eating a crisp (chip for you guys
)