Similar to eels, the hagfish is the only animal with skulls but no spine. Instead, they have separate bone sections in their backs that function like a spine. Hagfish tend to spend a lot of their time dormant to conserve energy, usually moving only to eat every once in a while.

The jellyfish called Turritopsis dohrnii has been dubbed the immortal jellyfish because it can revert to a younger polyp form after reaching its fully-grown state.

Marine iguanas are also known for their very efficient salt glands, where they "sneeze" out salt. Because they feed underwater, they ingest a large amount of saltwater. In order to prevent dehydration, they must expel salt without expelling water, so they have specialized glands that remove salt from their blood.

There are fifty different species of gall crabs, all small in size. To avoid predators, they form depressions in living coral, a small pit or cave that the crab then lives in. The home also provides easy access to food. The crabs feed on mucus that the coral produces and also other algae bits that they can reach from inside their small coral caves.

The Pistol Shrimp can use its claw to create bubbles that can fly out at 60 miles per hour, fast enough to kill or stun their prey. When these bubbles pop they can reach 210 decibels. An actual gunshot is only around 140-175 decibels.

Seashells have long been perceived as tiny little devices that can mimic the static, hissing noise of the water. What they're actually doing is acting as a resonator, or a cavity that allows sound to vibrate. By holding the shell up to your ear, you're hearing the ambient noise around you amplified. All that whooshing air typically sounds a lot like the movement of cascading waves.

Every year, shipping containers get lost in the ocean, and oil spills are unfortunately common. But in 1966, the United States managed to lose a hydrogen bomb at sea and became the center of an intense 80 day search. it was eventually found by francisco simó orts, who had seen where it was dropped.

Scientists say that "fish rain" usually occurs when swirling whirlwinds over relatively shallow water develops into waterspouts and sucks in almost anything in the water including fish, eels and even frogs. The marine life can be carried long distances by buffeting clouds even when the waterspout stops spinning.

The world's most venomous fish is a close relative to the scorpionfishes, known as the stonefish. Through its dorsal fin spines, the stonefish can inject a venom that is capable of killing an adult person in less than an hour

Let's go back to our roots and talk about freshwater fish you can probably catch. In the deep waters of Eastern Europe and Western Asia lives the largest-bodied European freshwater fish, the Wels catfish also known as sheatfish. The Wels catfish can grow up to 3 meters (9ft 11in) and weigh up to 150 kilograms (330lbs). Though the fish is considered a trophy to some anglers it is also an extremely invasive species having a mean risk score of 21.5 out of a possible 54. which means that it can inhabit different habitat types and will consume a wide range of food items within its environment. And with the female Wels catfish laying up to 700,000 eggs at a time and the male strongly guarding the eggs, an invasion can easily happen where these impacts could easily be felt.