Seahorses are truly unique, and not just because of their unusual equine shape. Unlike most other fish, they are monogamous and mate for life. Rarer still, they are among the only animal species on Earth in which the male bears the unborn young.
Pom pom crabs and sea anemones have their own tiny cheer squads. The crabs wave the stinging anemones around to defend themselves against predators, while the anemones collect food particles they can feast on after sharing with their crab besties.