The Great Debate: Are Octopus Fish?

are octopus fish

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Octopuses are some of the most unearthly-looking creatures that inhabit our oceans. They have large heads, eight tentacles, and are extremely intelligent.

They are found in all of the world’s oceans and are extremely resilient, often hiding in dens or found roaming shallow coastal waters in search of food.

Octopuses have three hearts and blue blood, along with nine brains, one for each tentacle as well as one in its head.

These incredibly unique animals are some of the most fascinating on earth. But what category of animal do they belong to? Are Octopus fish?

Octopuses are cephalopod mollusks. This class of animal also includes squid, cuttlefish, and nautilus. They are a small group of highly advanced and organized marine animals

Are Octopus Considered Fish?

Octopuses and fish both live in the ocean, but they are far from the same. An octopus is a mollusk, but to be more specific, they belong to a unique class of mollusk known as cephalopods.

An octopus is a soft-bodied, eight-limbed mollusk of the order Octopoda. The order consists of 300 species of octopus and is grouped within the class of Cephalopoda with squids, cuttlefish, and nautiloids

That said, both fish and octopuses share the same classification strata of the Animalia family. Fish are known as Chordata and octopuses are known as a mollusk.

One of the biggest differences between a fish and an octopus is that fish have a backbone and a skeleton, which makes them vertebrates.

Whereas octopuses have no skeleton or spine, they are defined as invertebrates.

The Differences Between Fish And Octopus

Whilst fish and octopuses live in the same environment and both have two eyes and the ability to extract oxygen from the water, there are plenty of differences between the two.

Below are some of the main differences between the two:

  1. Fish have scales, whereas octopuses do not.
  2. Octopuses have eight appendages.
  3. Octopi are much more intelligent than fish, debatably the smartest animals in the ocean.
  4. Octopus creates propulsion through jets of water, whereas fish use wave-like movement to get around the ocean
  5. Octopuses are invertebrates, but fish are vertebrates.

Are Octopus Fish Or Mammals?

An octopus is not a mammal nor a fish, they are in fact an invertebrate mollusk as they do not have a skeleton or backbone.

A mammal is a warm-blooded vertebrate animal of a class that is distinguished by the possession of hair or fur, females that secrete milk for the nourishment of their young and give birth to live young.

Octopuses do none of those things, unlike whales for example which are classified as marine mammals.

Although octopuses do have gills that allow them to extract oxygen from the water for them to survive, this does not place them in the fish category.

The word cephalopod quite literally means “head foot”, which very well describes an octopus as they have their feet attached to their head, well… arms technically speaking.

Cephalopods have the most advanced nervous system of all invertebrate animals and are active hunters.

Octopuses feed on crabs, snails, clams, sea stars, and much more.

They use their tentacles to grab onto prey and hold them in place, before piercing them with venom with their parrot-like beak and proceeding the consume the liquified prey.

Final Thoughts

So, are octopus fish? No, they are cephalopod mollusks that are invertebrates. They are completely different to fish and have a lot of different characteristics.

Octopuses have eight arms and a bulbous head, they have three hearts, nine brains and are some of the most intelligent animals on the planet.

Fish, on the other hand, are not really as intelligent and they are vertebrates as they do have a backbone and a skeletal system.

Many people use the word “fish” to generalize animals that live in the ocean, but there are many different types that must be clarified.

Marine mammals, cetaceans, pinnipeds, cephalopods, fissipeds, and much more are all different categories of marine life.

Hopefully, this post has been helpful and you now know why octopuses are not fish and are instead cephalopod mollusks that below to a small family along with cuttlefish, squid, and more.

Thanks for taking the time to read this post and feel free to share it with others who may find it useful.