as soon as my fishless cycle is finished i plan on getting blue legged hermits. i read they are detritus eaters. well my tank has never had fish. is the very small amount of "fall off" from the live rock enough to sustain him for a few weeks? or should i use a fish flake and let it drop to the bottom? or some kind of sinking pellet? also how do i know when he needs a new shell? i was watching them at the lfs and they look like very active little critters crawling around until they find something and then doing a "head stand" in the sand to pick something out! its really cool. just want to know more about their care than what is listed on live aquaria.