By-the-wind sailor (Velella velella), floating on the surface of the sea outside Newport Beach, California, United States of America, North America

Dangerous current warning sign at a beach on the outskirts of Sydney, New South Wales, Australia, Pacific

striped remora or live sharksucker remora cleaning scraps from inside the mouth of a lemon shark Negaprion brevirostris resting on the bottom is a strong current Thought to be a parasite this is one of the first images showing a benefit for the shark in this relationship West End Grand Bahamas Atlantic Ocean