Barnacles can extend it's penis up to 30 times the length of its body. Barnacles are sessile and unable to move from their settled location. In order to overcome this motility problem, the barnacle can extend it penis to any near neighbour in order to impregnate them with it's sperm.
Starting Out: for those people just in the hobby ( 23 items ) Starting out in the reef keeping hobby? Then this catagory covers some of the more basic questions on setting up an aquarium for the first time.
Things to do with filtration and the associated equipment and methodology required.