Fish Intelligence: Do Fish Have Brains? ❘ Fish Camp Rehab

The most frequent question asked by people is Do fish have brains? I’m not convinced that people need to be able to answer this question, but we’ll attempt to provide all the answers you need in this article.

Do fishes have emotions? Some people believe that fish are inscrutable animals that can’t experience emotions, retain memories or experience pain.

Many may even believe that fish do not have brains!

It’s likely because the majority of people aren’t aware of this aquatic world and don’t understand the ways that fish are able to live within their environments.

It is easy to assume that fish are unintelligent animals since their faces are stiff and they don’t blink or shout.

But, if you take a look at it closely, you’ll realize that everything is a myth!

The myth of fish having no brains or having a 3-second memory is simply NOT true!

Fish show a range of indicators of intelligence. These include being able to remember things, feeling pain and stress, showing social intelligence, as well as the capacity to communicate.

Continue reading to discover how clever different fish species could be.

Do Fish Have Brains Yes or No?

Yes, fish have brains.

The myth of fish don’t have brains or aren’t brains or have the 3-second memory is simply NOT true!

The next time someone asks you if fish has brains, you are able to say yes!

Brain size is measured in relation to body weight and size.

As compared to other vertebrates the majority of fish have smaller brain-to-body ratios.

But, there are also species that have very advanced and huge brains.

For example, An African freshwater fish called”the Electrogenic Elephantnose has one of the highest ratios of body weight to the brain in vertebrates.

Its brain is even bigger than the human brain.

It additionally has the top oxygen brain-to-body consumption rate among vertebrates.

Sharks and Mormyrids possess enormous brains in relation to their bodies too.

Cephalopods like Octopuses, have developed brains and are capable of learning and growing.

Certain fish even surpass youngsters and chimpanzees in some cognitive tasks.

For instance, German and American scientists have compared a species of fish called Cleaner Wrasse with three primate species: capuchin monkeys orangutans, and chimpanzees.

They let them select their meals from two dishes.

A plate of red and the other blue.

They continued to remove the blue plate, which took about two minutes.

The fish soon realized which plate would soon be taken away and began eating off the blue plate to gain more food.

The primates weren’t able to realize the connection, and eventually were deprived of food.

Fish Intelligence

What is intelligence? And how can it be determined in fish?

Wikipedia states that it’s the process of collecting memories, storing them in memory retrieving, combining, making connections, and applying in new contexts the information and abilities. Simply put, it’s a method of learning new skills.

The most important points to remember:

  • Storage and Comparing of information
  • Finding information
  • Combining information
  • Processing
  • Learning

Imagine adding something new to your aquarium or new fish. They are hesitant about the new addition to their environment and it can take just a few hours for them to research and try this new species of fish, or piece of equipment until they feel they’re secure getting close to them.

A study by Calum Brown at Macquarie University said that fish have larger brains than other animals and even primates when compared to their body weight. In reality, they’re smarter than we think.

Electrogenic elephant nose fish is one of the African freshwater fish is one of the highest body-to-brain weight ratios of vertebrates (slightly more than humans).

Brain Size

The size of a brain is typically measured by the body’s weight and size. In the case of the brain of a fish generally, it’s smaller in comparison with the dimensions of their body in comparison to other vertebrates.

Do Fishes Think?

Many people view fish as being less than chickens, cows, pigs as well as other animals on the land.

We’ve got a vague notion that fish aren’t as smart (think of the popular belief that fish possess a three-second memory) and we genuinely wonder whether they are able to be able to feel pain.

Australian bioscientist Culum Brown offers a controversial argument to defend his position on the issue, based on years of study into the behavior of fish and their ability to learn. “They’re just not any less intelligent or sophisticated than terrestrial animals,” Culum Brown asserts. “That idea is a total myth.”

Fish do not possess a three-second memory, Brown has discovered — in fact, they are taught to avoid traps and then remember the event one year later.

Fish learn from each fellow fish, can recognize other fish they’ve shared time with before, understand their place in the fish social hierarchy, and can remember intricate spatial maps of their surroundings.

There’s also proof, Brown has written that they make use of tools.

Fish don’t only consume, mate, hunt, and even raise children.

They are also able to perform complicated tasks.

1. Feeling Pain

The majority of people believe that fish don’t have nerve systems, and thus don’t sense pain.

Many vegetarians even eat fish due to this myth.

Researchers have discovered that like humans fish have nerves known as “pain receptors” that convey pain.

They may not feel pain in the same way that we, however, they possess the right equipment to experience pain.

In this way, they stay clear of painful experiences.

Fish also contain brain chemicals, known as neurotransmitters including serotonin and dopamine. These can cause feelings of fear, anxiety, fear, pain, and thirst.

These chemicals constitute the programmers.

Combining the hardware and the software it is possible to be certain that fish will be in pain.

Future experiments could provide us with greater insight into the issue.

In a study, fish were given acetic acid or bee venom on the lips.

They began to rub their lips on the corners of the aquarium or on the gravel and then breathe more quickly.

They also weren’t reacting to stressful situations or were hurt as they usually would.

They were injected with aspirin lidocaine and morphine which caused pain-related symptoms to disappear.

2. Memory

Do fish have memory?

Goldfish are equipped with a three-second memory.

That’s simply not the case!

In a study, goldfish can recall the color of a food dispenser even after a year without being able to see it.

Fish may remember individuals who they lost fights against and the fish that have fought them before.

A fish that is red will recognize its mate after being separated for 30 consecutive days.

Certain fish species are harder to catch after being caught by anglers.

They are more likely to stay away from places in which they’ve been attacked or had stress.

A few fishes can remember their trainers after months without them.

Once fish have learned how to escape from a trap, they are able to recall the escape route for one year later.

Certain varieties can be taught to press a bar to get food, and then remember the trick after several months of not having seen the bar.

Fish make use of visual landmarks, odors, and light sources to navigate through the ocean without becoming lost.

In a study, Israeli scientists played a sound on a speaker before feeding a bunch of fish.

After a few times, they learned to be around the speaker every time they heard the sound and wait to be fed.

Then, the researchers let the fish go into the sea.

After a few months, they broadcast the sound of the sea by using a loudspeaker.

The fish were able to remember the sound and moved to the speaker in search of food.

This phenomenon is known as classical conditioning. It was first observed in dogs by a Russian scientist called Ivan Pavlov.

From the early 1890s onward, the method was repeated with a variety of animals, such as horses, ducks, and even elephants.

3. Social Intelligence

Like other animals, fish that live within a social group is able to recognize one another.

If a fish is forced to decide between living with strangers and going into the tank with its previous buddies, it’ll pick the latter option.

Additionally, fish are able to recognize stronger, larger species and predators, and alter their behavior toward them.

In the case of example when a fish loses in a battle against another fish, it’ll be able to remember to stay clear of this particular fish in the next.

As part of an experiment, men fought with a female who was an observer.

Then the males were permitted to spend time with the female who was watching as well as a brand new female.

The fish that won preferred to be with both of them, while the loser did not want to spend in the company of the female who was watching it lose the fight.

Additionally, males are generally less aggressive as a female is watching them, as females tend to be with males who are less aggressive.

But, if a male is in the room they are more likely to be aggressive and fight more violently.

Fish are also aware of territorial neighbors and will try to avoid them.

The same is true for bullies who have deprived their victims of food.

4. Deception

Certain fish are clever and fool other fish.

For example, Threespine Stickleback males can deter predators that want to attack their nests and then eat their eggs.

A few Bowfin fish attempt to frighten predators by escaping and thrashing around like an injured fish in order to keep their fries.

Certain species of cichlids catch their prey with an innovative technique called death feigning.

They’ll drop to the ground and stop like they’re dead or injured.

If the prey comes close enough, believing they’re dealing with a decaying carcass, predators attack them.

If this isn’t a sign of intelligence, then what does?

5. Feeling Stress

Anyone who has kept fish is aware that stress can cause fish to suffer.

Variations in the temperature, pH levels ammonia spikes, and a decrease in the levels of dissolved oxygen along with other causes could stress fish.

Stress can make them more susceptible to many diseases.

The physical reaction is known as Stress-Induced Hyperthermia, also known as Emotional Fever that can be caused by stress or a stressful event.

The name suggests that the body’s temperature increases similar to an illness.

It was thought that fish could not be stressed, and therefore would not experience emotional fever however, mammals, birds, and reptiles can.

To show that fish are conscious animals that be aware of stress, scientists conducted an experiment.

Fish are cold-blooded mammals.

They are moved to areas where the temperature of the water is close to their physiological condition.

In this study, researchers trapped a zebrafish inside the tank with a net in which it was subjected to stress.

Then they let it out into a tank that has several temperature zones.

The fish spent the majority part of the time in warm waters.

Contrary to this, the control zebrafish that weren’t affected by stress remained in the warmer areas.

Fish aren’t able to control their temperature in the body, which means that the stress-suffering fish’s body temperature increases due to stress.

6. Cooperation

Animals are known to join in groups to accomplish common goals, including hunting.

A variety of fish species ask for help from one another when they wish to fight their prey.

Some are assisted by smaller or slim predators after they locate the hiding place of their prey usually when they are unable to take it down on their own.

A Bluestreak-like fish Cleaner Wrasse assists other species of fish to remove parasites by eating the parasites.

The fish that is infected, also known as the “client,” will head to a wrasse’s hive and then wait for it to cleanse its body.

Sometimes, the wrasses will do a sloppy job and eat body mucus, which causes the victim to flee.

However, wrasses will not perform this behavior if customers are watching them.

They may want to keep an excellent reputation.

7. Tool Use and Construction

While fish are limited to their mouths for holding objects but they can make use of various objects in their favor.

For instance, certain Wrasse species are able to hold bivalves or sea urchins using their mouths, while pounding on rocks in order to tear them into pieces.

A few fish place their eggs on leaves, so they can remove the leaf and carry it away when predators approach their nest.

Archerfish may squirt water on the surface to attract insects, and they’ll then sink to the bottom of the sea.

Whitetail Damselfish are able to cleanse a rock’s surface blowing sand grains before laying their eggs in the rocks.

Many fish can construct nests by themselves by digging and drilling into the sand or stacking up coral pieces and sand to create mounds.

Male sticklebacks utilize the secretions of their kidneys to join pieces of plants together to create a nest.

8. Communication

Fish communicate with them, and even communicate with each other!

They communicate with one another by using low-frequency sounds such as Squeaks, squeals, and squeaks that we cannot hear except with specific instruments.

They also communicate with one another through body language.

For example, a lionfish can move its fins behind in a specific method to attract other fish to join in the hunt.

9. Playing

 In the case of animals, playing is an indication of intelligence.

One example of a fish that is playing is one of the Elephant Nose fish with one of the largest brain-to-body-weight ratios in invertebrates.

As part of an experiment, the was a fish that carried a small ball of aluminum foil into the filter outflow tube of the aquarium and the current drove it away.

The fish would then follow at it, repeating the process.

If cichlids spot the sight of a ball that bounces or a floating thermometer floating, they begin playing with it, making it a spin.

10. Recognize Humans

Do they know and appreciate your personality? Perhaps there are positive signals for you.

Not only are fish able to identify human faces with complete accuracy, however, but some fish can also recognize specific human faces.

Fish are more intelligent than humans and can discern different particulars and nuances, which makes every fish appear distinct.

11. Relationships

Affection and building relationships with a person is also a sign of intelligence and having an innate brain.

A lot of fish use the surroundings and the environment to draw opposite partners. The pufferfish creates beautiful designs and sandcastles on the ocean floor to draw a partner.

Others fish employ similar techniques and some develop a new style to draw a new mate. What do we humans want to build muscles to appear better and be more attractive to partners? Some fish are the same way. Some fish inflate their bodies by drawing air into it or even water in order to make themselves appear larger and more attractive.


Did you get the right answer to your question, do fish have brains?

Yes, they have brains. Fish are smarter than we could imagine them to be. Their brains help them to react according to the circumstance they encounter.

To ensure survival in the aquatic world, the brain of fish helps to make sure they take all the required actions.

They possess an impressive memory that permits them to distinguish the signs of potential danger or their owners, as well as other things.

Why are we thinking of fish as being stupid? We don’t really interact with fish in any way that is meaningful.

It is true that the aquatic world is completely different from the terrestrial world and, in the end in the event that you’ve not observed an animal within its surroundings and comprehended the mechanisms behind it then you’re never ever going to be able to fully comprehend it.


Dibyajyoti Bordoloi is the creator and author of, a third-generation experienced fish keeper and owner of a successful pet breeding farm. He is also a member of the Center for Wildlife Rehabilitation And Conservation (Assam), the Marine Aquarium Societies of North East India, and the Kaziranga Nature Conservancy of Assam.

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