Do fish have brain?

Do Fish Have Brain? All Myths Debunked:

When you keep adding food to one side of the tank, you will notice that at the time of feeding your fish will automatically come to that side. This behavior answers the question that do fish have a brain?

So, yes fish do have a brain and quite developed ones. All the basic physical functions such as swimming, eating, and responding to stimuli are controlled by a well-developed brain.

Let’s discuss the function and anatomy of a fish’s brain in detail.

3-Second Memory of a Goldfish:

Have you ever heard about 3-second memory of goldfish, do you think it’s true or just a myth? When it comes to memory goldfish definitely have more than a mere 3-second of memory.

There can be several experiments that not only goldfish, but other fishes as well can remember things for days, weeks, months, or even years.

A simple experiment to check a fish’s memory is a reward system. If moving through a red loop earns them a reward and green one doesn’t. Your fish will remember that for months and avoid things or hurdles with green color.

Thus, completely blocking this color from memory and giving preference to the color that earned the reward.

This simple experiment speaks clearly that fish has greater memory than 3 seconds.

Are Fish Intelligent?

Well, underwater creatures are ranked pretty high in terms of intelligence. Just as octopuses having a greater brain to body size than most animals.

But the question is,

What is Intelligence?

It is the ability to understand and deal with new situations and to adapt to the environment. To put it simply it is the process of learning new things and solutions to problems.

Intelligence is a combination of

  • Storage of information
  • Combining information
  • Processing it
  • Retrieving it from older memory.

Thus, whenever a new tankmate is added to an aquarium it is thoroughly checked and inspected by the previous tankmates. This is clear evidence of how intelligent fishes are and how they analyze their environment.

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How is Intelligence Measured in Fishes?

Intelligence is a direct measure of brain size and fishes have an incredible brain-to-body mass.

Brain size is measured in relation to the size and weight of the body. Next to mammals and birds, fishes have the greatest brain-to-body ratio.

Greatest Brain to Body Ratio:

Although fishes usually have a small brain-to-body ratio, some fish are exceptionally intelligent.

Some species of sharks, sperm whales, manta rays, dolphins, and orcas have impressive and large brains with extraordinary intelligence.

Sperm Whale Brain Size:

Sperm whales have one of the largest brains in any animal species present. Typically, sperm whales have about 20 pounds or 10kg of brain size. Thus, sperm whales are quite intelligent and have an impressive memory.

Electrogenic Elephant nose Fish Brain Size:

This African freshwater fish has a small body but an incredibly large brain substance. Thus, the elephant nose fish is one of the most intelligent underwater creatures to exist.

Structure of Brain in Fish:

Surprisingly enough, a fishes’ brain is no different from that of humans. Areas such as the cerebellum, cerebrum, medulla, amygdala, and hippocampus are anatomically homologous to those in humans.

Moreover, fish have brain cells called “Neurons” that are organized to process environmental information in the fish’s best interest.

Zebrafish have around 10 million neurons in their brain. This widespread network enables them to process information and respond accordingly.

Absence of Neocortex:

According to studies conducted on fish’s brain indicates that fish usually lack a neocortex. The absence of this region has a greater effect on sleep. This way fish can not experience changes in brain activity during sleep or rest periods.

Fish sleep resembles much like humans except for the fact that there is no brain activity during sleep in fish.

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The function of the brain in fish:

All the physical responses, swimming, sleeping, memory, and protection from predators are directed by the brain. Following are the most important functions performed by the brain.

Detection of food:

One of the primary functions of the brain is the search and then detection of food. Both gustatory and olfactory systems are involved in the detection of food that is controlled by the brain.


Camouflage ability in fish is the consequence of a highly developed brain. To hide from predators, camouflage is a protective mechanism.


The fact that fish knows to safeguard their offspring, get them food, and mating strategies are all thanks to highly functioning brain areas.


Hunting is an impressive feat that requires skills and intelligence which is a function of the brain. Thus, amazing hunting schemes are indicative of the brain.

Protection from a predator:

Hiding in rocks, camouflage, or fighting back all are responses that require deep insight, thinking, and intelligence. Coping with dangerous predators with skills indicates that fishes are quite brainy.

Formation of Nest:

The formation of a nest is a highly impressive trait that is performed by fishes having a higher brain-to-body mass.


Last but not least impressive memory of fishes that can last a lifetime is directly proportional to brain size.

Thus, all the above-mentioned processes are indicative that fishes are brainy animals, and they have amazing brains.

Pain Perception is a Function of Brain:

Well, one of the most frequently asked questions is that do fish feel pain?

The answer is “yes, fish do feel pain” and is due to the presence of a well-developed cerebral cortex. There are nociceptors (pain receptors) located all over their skin and are quite active in pain perception.

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 These receptors are sensitive to rise in temperature, extremes of pressure, and the presence of toxic chemicals. Thus, the pain felt by fish is quite different from that felt by humans, but the process is quite the same.

Frequently Asked Questions (FAQs):

What is the most intelligent fish in the world?

Although, many sharks, whales, rays, and dolphins are quite intelligent. Nowadays, the Comet goldfish is considered to be the most intelligent fish alive. They are pretty extraordinary in learning and skills.

What is the IQ of a goldfish?

According to the previously developed IQ mapping fish has an IQ of 35-40, which is not impressive. Today after multiple research it is known that fish is more intelligent than thought.

Do fish recognize their owner?

Although it is hard to believe fishes do recognize their owners and can also remember them for quite a long time. They can even identify their owner within a group. This is because the way fish interact with us is different from how we interact. Fishes are intelligent and it is proven by this fact.


Well from all the debate it is clear that fish do have brains and pretty developed ones. Fishes are intelligent animals that can even remember and recognize their owners. The 3-second memory of a fish is just a myth and nothing more.

When it comes to memory fish has quite impressive memory that can last longer than though. Their extraordinary protection methods and their ability to understand and manage a given situation prove that fishes are very brainy animals.

All the above-mentioned facts determine that fish are intelligent, fish do feel pain and fishes do sleep as well.

That’s all for today, hope to answer more of your questions in the future.

Best of luck with your fish!!!!

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