It’s got one of the (arguably) weirdest faces in the ocean, and the hammerhead shark is on nearly every diver’s bucket list.

Touching seahorses to manipulate them for pictures (and using a strong flash) is a big no-no, as it causes the animals much stress.

The nautilus is a living fossil, unchanged for hundreds of millions of years. Although divers see them infrequently, they are most common in the tropical western Pacific.

With impressive teeth and vibrant colors, titan triggerfish are the biggest among the species. And although they’re beautiful, divers should beware of this territorial fish.