|Marine leeches are blood-sucking parasites that feed on marine turtles (family Ozobranchidae) or fishes (family Piscicolidae). Turtle leeches spend their entire life cycle attached to the turtle. During heavy infestations, the turtle may be harmed due to enormous blood loss. Fish leeches are temporary parasites that leave their hosts after one or a few meals. Some take shelter amid seagrasses or rocks and may attach themselves to crustaceans until they are ready for their next meal. Others only leave their hosts to lay their eggs and then quickly find another host. Some fish leeches attach only to a single species of fish. Others are not so picky and will attach to a variety of fishes. There are only a handful of marine leech species found in the Gulf of Mexico (about 9).