Do Fish Have a Brain? You Will Be Surprised!

Have you every wondered “Do Fish Have A Brain?” Did you realise that fish don’t have a 3 second memory, its a myth. So do fish have a brain?

Most fish do have brains, they are very small relative to their body size, But some fish such as mormyrids and sharks have very large brains relative to their body size.

do fish have a brain

Do Fish Have Thoughts?

Fish having thoughts or consciousness has been a controversial issue as different researchers have different opinions and points of view. Until recently, most people refer to fish as animals without consciousness and emotions.

Researches carried out experiments that showed that fishes do have emotion, thoughts, and consciousness.

Some researchers claim that fish do not have emotions or thoughts because they lack the cerebral cortex, a part of the brain. These researchers also claim that fish have little capacity for memory, learning, thoughts, and reasoning.

They believe fish do not have this kind of behavior and cannot experience suffering.

Other researchers claim that although fish have small brains, they can also exhibit some traits. Morphological and behavioral analyses also indicate brain structures in fish linked to those of vertebrates.

Fish have structures similar to structures in vertebrates, like the amygdala responsible for emotions in mammals, and the hippocampus responsible for spatial memory and learning.

After carrying out experiments, the opinion of fish being emotionless began to change as a result showed that they could develop a situation known as emotional fever. If they can have emotion, it means they can also be conscious and have thoughts concerning issues.

There are not enough facts to show this, but an insight into this will occur this era.

Do Fish Have Feelings?

Many researchers spend a lot of time pondering the emotional status of fish. Many people think fish do not have feelings, but they are wrong. Like every other vertebrate, they have feelings and can feel pain, can be happy, sad, and even depressed.

Researchers experiments showed that fish can feel pain. They injected the fish with saline and acidic solution and placed a pain-killing solution on the other side of the tank.

They noticed the fish migrating to the parts of the tank with the painkiller, showing they felt the injection’s pain.

When you have two fish in the tank, and one of the two fish dies or you remove it, you will notice a change in the other fish’s behavior. The fish will have reduced activity and will not eat as it does before. It shows the fish is sad or depressed about the situation of its tankmate.

You can also know your fish is happy when you feed it. You will notice the fish behavior when you move close to the tank; it will be happy and swimming around waiting for you to feed it. Fish have feelings, and they will react to several stimuli around them.

Do Fish Have Memory Recall?

Most people believe that fish only have a memory span of about 30 seconds. Contrary to that, fish can have a longer memory span and can recall things than you think. They can remember associations and context up to twelve days after the day it occurred.

The longer memory span also allows them to remember the face of their owner.

They will move to the surface when they see their owner expecting food but will move away when strangers come close to the tank. Other fish like salmon also have a high retentive capacity, knowing their birthplace and returning to give birth.

What Fish Does Not Have a Brain?

A stable structure in fish is the brain; even those without backbones have skulls that protect the brain. Although there are no fish without brains, there are fish-related sea animals that do not have brains.

It might be a great surprise to hear that some animals do not have brains. Some animals do not have a brain, and they live, feed, grow, and even some are venomous. Fish without brain include;

  • Jellyfish : The jellyfish is a dangerous animal with venomous parts but not a brain. Surprisingly, the fish is 95% water, making it a bag of water without any brain. There are about 200 species and over 900 million tons of jellyfish in the black sea only.
  • Starfish : Starfish, also referred to as sea stars, are among the most beautiful animals in the ocean. It has the shape of a star and does not have a brain. It also does not have blood, can regenerate, and feed and digest food outside its body.
  • Sea Cucumbers : Sea cucumbers are also one of the few creatures without a brain. They have leathery skin and take the shape of a worm with tube-like structures at their mouth. They have the same density as water, which allows them to push themselves up in the water and slowly drop back to the bottom of the ocean.
  • Sea Urchins : The sea urchin is a spiky sea creature without brains. It moves like the starfish using a water vascular system, where it changes the pressure and amount of water in its body. They feed on algae scraping off algae from sea structures.
  • Sea Squirts : The sea squirt is an amazing sea creature with a weird transformation. It begins its life being a larva with a small tiny brain. The creature starts to absorb and feed on the tadpole parts that made it chordate, including its brain. In no time, the animal loses its brain; it does not need the brain any longer, so it is not much of a loss.

What is the Smartest Fish?

There are several smart fish, but their smartness depends on how well you train them. You can train a little goldfish to become smarter than a dolphin; their intelligence depends on how well they acquire knowledge. There are also naturally smart fish like the east African cichlid that can recognize unfamiliar faces by looking at their face.

There is also the mangrove killifish that will feed on its peer egg but will never make the mistake of its own; what a smart fish! Dolphins are one of the most intelligent fish that can solve complex problems and interact socially. Also, a comet, a goldfish, is on the path of becoming the smartest fish as it can play basketball, football, limbo, and even fetch poles.

What is the Dumbest Fish?

Fishes are smart creatures, but some just exhibit a low-cost living. They go about not fascinating or doing anything that catches attention. An example of this fish is the sunfish; although it does respond to stimuli, it does nothing in particular.

 Do Fish Feel Pain?

Yes. Fish do feel pain even though it is different from the way humans feel theirs. They have a neuron that helps them detect potential harm like high pressure, high temperature, etc.


Every fish has a brain, but not all sea creatures have a brain. There are several sea creatures without brains, and they perform their daily activities correctly. Although some fish do not have backbones, these fish possess a brain protected by a skull.