Ceratium fusus is a protist that is found primarily in coastal waters, especially around the coast of the United Kingdom. These organisms are unique because they can undergo a special chemical reaction at night that helps defend them against predators. It provides defense by attracting larger predators that prey on the organisms that eat Ceratium fusus. Which characteristic of Ceratium fusus is being described? photosynthesis glass-like cell walls bioluminescence chitin cell walls.