These beautiful feather duster worms have a feather of around 6cm across. They need plenty of coral food / rotifers / cyclops added into the aquarium to help them grow. If your worm doesn't get enough food it may loose its feather. It will grow back, but smaller and smaller. The worms have one end that is more leathery that is where they attach from. They will stick them selves to rockwork, corals or even under the coral gravel. They prefer a place where the flow isn't too strong and where they can collect plenty of food.