They do not "steal food from corals", they do not "harm fish", they have no jaws and are are not predatory. They are scavengers and nothing comes close to their efficiency in your CUC. They are one of the first on the scene when something dies and needs to be cleaned up. This is usually why they get blamed. Their population is also self limiting, the more food that they have, the more of them you will find. If the needles irritate you, surgical gloves are the answer, which you should be wearing any time you are putting your hands where you cannot see them.