The ocean is one of the, if not the, largest habitats for life in the entire world, and unsurprisingly too. There are fish and marine animals in all of the different climates in the ocean, from the freezing temperatures of the arctic to the tropical areas of the great barrier reef, to even the darkest and deepest parts of the ocean. On the list, we’ve taken our pick of the weirdest and most unusual marine animals you’ll find in the ocean, under our waves.
Angler Fish
Why it’s unusual: It uses a bright lure to attract prey
Where is it found: The ocean floor

The angler fish is a well-known marine creature thanks to the success of the film Finding Nemo. So while it may not be unheard of, it definitely earns the moniker of unusual. Using its fin ray as a lure, it attracts and then devours its prey.
Interestingly the bioluminescence emitted from the lure comes from a symbiotic bacterium. These come in many shapes, some with an almost eel-like body but the one thing they have in common is their lure!
Nudibranch
Why it’s unusual: They are shell-less and breathe using devices outside their body
Where is it found: The ocean floor

These are more commonly known as the sea slug. The fact that they are called slugs might make you envision an earthbound slug and therefore induce feelings of revulsion.
However, the aquatic versions are often beautifully colored. As with many creatures the colorings are to deter prey suggesting that they are venomous and many species are. While we joke that slugs are snails that have “lost their shell” that is literally the case with Nudibranchs which have evolved to ditch their shells.
Sea Hare
Why it’s unusual: Have an internal shell
Where is it found: Globally

This creature looks more like a sea slug than a sea slug does, but it is actually an aquatic snail. Initially, this may seem unusual as it doesn’t appear to have a shell, but the sea hare has an internal shell and that alone makes it worthy of the list. They can shoot ink when threatened and have quite an engaging appearance.
Brine shrimp
Why it’s unusual: Type of shrimp that are millimeters long
Where is it found: Globally, in saltwater lakes and marshes

The brine shrimp are commonly referred to as sea monkeys. Given their popularity, it might surprise you that they make an appearance on this list. But these incredibly tiny shrimp can survive without metabolizing. Metabolism is the sum of all the chemical processes in an organism, and the brine shrimp can survive without any of that happening. It is not alone in this: Jellyfish polyps also can remain in that dormant state.
The Blue Whale
Why it’s unusual: The largest living creature on Earth
Where is it found: All oceans except the Arctic

This gigantic mammal makes the list purely because of its size. Despite all of the dinosaurs that once roamed our earth, the blue whale remains the biggest creature to have graced our planet. They are massive. It is suggested that an adult man could swim in one of its arteries. Its tongue, incredibly, weighs as much as an elephant. Additionally, despite its humongous size, its diet consists mostly of tiny krill. In fact, they are so small that the Blue Whale has to devour more than 40 million of them per day.
Leafy Seadragon
Why it’s unusual: A master of camouflage, looking like seaweed
Where is it found: Australia

The leafy seadragon is actually a member of the seahorse family, something that becomes more obvious when considering the shape of its head. Its bright colors and unusual shape make it one of the more interesting aquatic life forms. So interesting, in fact, that wildlife guru David Attenborough has commented that it is one of his favorite animals.
Seahorse
Why it’s unusual: One of the most inefficient swimmers in the ocean
Where is it found: Globally in tropical waters

The sea horse is a relative of the pipefish and as such, it has a long thin digestive tract that is notoriously poor at absorbing nutrients. As a result of this, the seahorse is in an almost perpetual state of feeding. These well-known and often sought-after animals are a wonderful addition to this list.
Red Handfish
Why it’s unusual: It can walk on the ocean floor with its fins
Where is it found: Southern Australia

Unfortunately, the Red Handfish is on the brink of extension and is native to just two small reefs. It would truly be a loss to the ocean.
Despite its unique look, there are other reasons to include it on a list of the weirdest marine animals. Specifically, its unique travel style. They use their fins to move across the reefs in a way that makes them look like they’re walking. This is a technique used by certain members of the Goby family, such as mudskippers.
Blobfish
Why it’s unusual: A deep sea fish with a peculiar face
Where is it found: Australia

The blobfish is also known as a Psychrolutes marcidus. Due to living in such great depths, the fish has an incredibly unusual shape. It’s gained some amount of fame due to its appearance and is mainly found off the coasts of Australia, Tasmania, and New Zealand.
Lionfish
Why it’s unusual: Very colorful and incredibly venomous
Where is it found: Eastern Atlantic

The lionfish is one of the most distinctive-looking fish. It has an almost Samurai-like quality with its luxurious spiny-looking fins that flow from it like an ancient warrior’s robe. The lionfish is a vicious hunter and any marine aquarium keeper will tell you that you don’t want to keep these beautiful fish in a tank with another species otherwise, you are just going to end up with some pretty expensive food.
FAQs
Can you eat Lionfish?
Yes, in some parts of the world, it is encouraged. For example, the species are not native to the Florida coast and have caused havoc to the natural food chain, so removing them is encouraged. A note of caution: they do have venomous spines, but if prepared properly they are delicious and sustainable.
How long have sharks been around?
Around 450 million years. In fact, sharks have been on the earth longer than trees have. This is because life evolved in the sea before spreading to the land, but there is something about trees that make them seem eternal somehow, like they have always been there.
What is the rarest marine creature?
There are many rare marine creatures, but one of the rarest is the vaquita. It is on the edge of extinction, with around 10 remaining individuals in the entire world.
What is the ugliest fish on earth?
Unfortunately for the blobfish, it is often labeled the ugliest fish on earth. This is due to its strange shape, indistinct color, and rounded face.