Evolution alone is an amazing thing - but species that evolve together can be all the more spectacular, protecting, feeding and cleaning one another in incredible ways. Sharks pair with fish, fish with shrimp and shrimp with sea cucumbers and much much more. From boxing crabs that wield poisonous anemones as weapons to shrimp that scour the mouths of electric eels, here are seven of the most radical symbiotic relationships from the shallowest to the deepest waters of our world.
So how did we get here anyway? Call it evolution, call it luck, but really the best and brightest creatures above and below the waves found powerful allies. In some cases these are completely unexpected - predator and prey, friend and foe - but the ones that stuck it out and stayed friends through the toughest of times managed to make it to today's oceans and seas.