Are Seahorses a Horse or a Fish? Solving a Fishy Question.

4 min read

Seahorses get their name because their head is shaped somewhat like a horse and they live in the sea.


It is an amusing name and their unique appearance makes them an attractive aquarium pet since aquariums are for people to watch or observe.

But is a seahorse really a horse?

Although seahorses don’t look like what many people picture a fish to like, a seahorse is a fish. Seahorses belong to the fish class Actinopterygii which also includes salmon and tuna. Seahorses, pipefish, and sea dragons belong to the family Syngnathidae named from the greek roots syn which means together and gnathus which means jaws.

Seahorses scientific name hippocampus is from greek roots hippo meaning horse and campus meaning sea monster.

Is a Seahorse a Fish or a Mammal?

A seahorse is classified as a fish because they live in water, breathe through their gills and have a swim bladder like a normal fish.

What sets them apart is the fact that they don’t have caudal fins like normal fish.

A caudal fin is in the fish’s tail and is what the fish use to move them forward

This is why seahorses are very slow swimmers. All seahorses have is a dorsal fin on their back which they can flap extremely fast to propel themselves forward but swimming upright is not very aerodynamic and still makes them slow swimmers compared to other fishes.

They also have a long snake-like tail and a neck and snout that points down, unlike a normal fish.

Their head is shaped like a horse head which gives them their name and is also unique compared to other fish.

Mammals typically have fur, are nourished with milk from their mothers, and live on land, of which a seahorse are none of these, so you can see why they are not mammals.

Are Seahorses Fish Or Invertebrates?


Seahorses are a vertebrate from the scientific class of Phylum Chordata because they have a backbone, while an invertebrate is defined as not having a backbone.

The backbone or backbones as you might say are part of the seahorse’s defense against predators.

The backbone of the seahorse is made up of several plates that can slide past each other when they are compressed and helps the seahorse withstand a crunching force that would kill other fish. Because of these bony plates, a seahorse can survive compression of up to 50 percent which is half of its body because of the high mineral content in its bones.

Minerals can make bones brittle and seahorses have adapted to have only 40 percent of minerals in their bones, while the other 60 percent of their bones are water and natural compounds, which allow the bones to resist a great amount of pressure.

Other than plates, the backbone of a seahorse is like rings that go all the way down to the end of their tail with everything vital protected inside the rings.

Most creatures won’t eat a seahorse, while others will give up when they bite down hard and can’t bite through. A weird defense mechanism to say the least but effective.

Frequently Asked Questions About Is a Seahorse a Fish or a Horse?

Why Is A Seahorse Called A Horse?

Seahorse is the name given to a fish, but its head is shaped like a horse, and since it lives in the sea, it was named a seahorse. Seahorse is the common name given to this fish, while scientific names are given to keep specific species from getting mixed up.

It has been scientifically proven that seahorses are a type of fish but when naming a species, the name can be anything, it doesn’t have to be specifically related to what the creature actually is.

The scientific name for a seahorse is hippocampus from the greek roots hippo meaning horse and campus meaning sea monster. However, hippocampus is a boring name and not as attractive as ‘Seahorse’, especially for commercial sale for something like aquariums.

A better example of this would be sea-monkeys, so named because the creator of the ‘brand’ wanted to market brine shrimp to children as pets. Sea-monkeys have long tails like monkeys and they live in salt lakes, but they don’t really look like monkeys and they certainly don’t live in the sea.

Would a child rather buy something called brine shrimp or something called sea-monkeys?

Scientific names are to keep different species from getting mixed up while common names are for the general public so they can refer to an animal or pet without haveing to memorize scientific names that can be hard to pronounce.

Why Is A Seahorse Not A Horse?

A seahorse is not a horse because it has been scientifically proven that it is a fish.

Seahorse is just the common name given to this fish because its head is shaped like a horse and it lives in the sea.

Common names are given to species, so the general public doesn’t have to memorize scientific names that can be boring and very difficult to spell or pronounce.

Are Seahorses In The Horse Family?


Seahorses are not in the horse family because they are fish.

Seahorse is just the common name given to this fish because its head is shaped like a horse and it lives in the sea.

Common names are for the general public so they don’t have to memorize, spell or pronounce scientific names which are created to keep species from getting mixed up. Scientific names can also be rather boring, especially for commercial purposes like a home aquarium.


I hope we have thoroughly explained that a seahorse is a fish, not a horse, and why it is called a seahorse.

If you like the way that we explain things in detail, without all of the scientific mumbo jumbo, please check out out there articles about sehorses. Enjoy!

Written by:

Pet Aquariums

Have you any questions?