Do Fish Have Brains? (Yes BUT You Should Know These…)

Perhaps you’ve been told that you have the memory of a goldfish. You may have wondered, if fish have such poor memories, do fish even have a brain?

Short Answer

Science says yes! Fish actually have larger brains compared to other animals.

In fact, fish have some of the best memories in the animal kingdom too. 

Below, we’ll tell you about some fish that have the biggest brains. We will also share some cool things fish do with their brains in nature!

Which Fish Have the Biggest Brains?

 image of Fish Have Brains

So how do we know fish even have brains? Easy: Scientists have dissected them to find out!

In dissecting these fish, they’ve discovered which ones have the biggest brains of all.  

If you’re wondering how a small fish could possibly be considered to have such a large brain, you’re not alone. While fish brains may be smaller than other animals’ brains, they have a larger brain-to-body mass ratio than other animals. 

The brain-to-body mass ratio compares the weight of an animal’s brain to the total weight of its body. Animals with higher brain-to-body mass ratios have larger, heavier brains compared to their body weight versus animals with low brain-to-body mass ratios. 

Some fish in particular are known for having a large brain-to-body mass ratio, including:

  • Manta rays
  • Sharks
  • Elephantfish

Though there are many more species of fish, these three are some of the most common fish with high brain-to-body mass ratios. Let’s take a closer look at their abilities.

Manta Rays

Manta rays have one of the largest brain-to-body mass ratios out of all species of fish! In fact, some manta rays have brains that are nearly ten times larger than the brain of a whale shark.

Scientists who have studied the brains of manta rays have identified areas of the brain dedicated to learning, communicating, and problem-solving. Some scientists even speculate that manta rays can recognize themselves in a mirror, which is a highly advanced sign of self-recognition. 

They are also skilled at clear communication. Manta rays have been shown to even communicate well with humans.

An example of this can be seen in a video of divers in the Ningaloo Reef in Western Australia. A manta ray with a fishing hook stuck under her eye approached the divers, flipped to show the hook, and waited patiently for them to remove it. 

After its removal, the manta ray sat there for a moment as if wishing the divers goodbye before swimming back off into the sea. 

With such a big brain, it’s not surprising that manta rays are one of the most curious and playful fish in all the ocean!

Sharks

If you’ve ever watched a shark documentary, you know just how intelligent yet misunderstood these sea creatures are. As some of the biggest fish in the sea, they also have one of the biggest brains. 

Fans of the Jaws film series may believe that sharks are simply mindless creatures looking for their next brutal attack, but they’d be wrong. Sharks are not only one of the oldest vertebrate species on earth, but they also engage in many complex behaviors. 

One of these complex behaviors is social learning. This means that sharks are able to learn new behaviors by observing other sharks engaging in that behavior, like if someone showed you a recipe and you were able to recreate that recipe later!

They also know how to problem-solve. One research project showed that sharks were able to remember the solutions to different puzzles for several months. 

Learning more about the cognitive abilities of sharks helps us understand their natural behaviors such as retrieving food and selecting optimal habitats. 

Elephantfish

Elephantfish are known for their giant brains! 

In fact, the Peters’s elephantnose fish is known for having the largest brain-to-body mass ratio of all vertebrates. This is because of their massive cerebellum, which is much larger than those of other animals.

Researchers suggest that over 200 species of elephantfish may have evolved to have such massive brains because of their ability to create electric fields. Their knollenorgans, or electric organs, generate electric fields as a way to:

  • Locate prey
  • Communicate with one another
  • Otherwise sense their environment

Because of their large brains, elephantfish show impressive intelligence compared to other fish. Their ability to communicate with one another through electrical impulses shows significant signal processing skills in these fish compared to other species. 

What Do Fish Do With Their Brains?

You may be wondering, what do fish even do with their brains? Don’t they just eat and swim all day?

Nope! Fish can actually do much more than swim and eat. Some of the things they can do will likely surprise you. 

Impressive aspects of a fish’s intelligence include their:

  • Memory function
  • Ability to learn new tricks
  • Natural instincts and behaviors

Without a brain, none of these things would be possible. Let’s take a look at these incredible fish abilities in more depth. 

Memory Function

Though you may have heard about a goldfish’s short memory, this is actually a lie! All fish have impressive memory functions. 

Have you ever seen your fish swimming to the top of the tank when you come over to feed them? That’s them proving they remember you!

Your fish have learned to associate you with food, showing that they remember that you come to feed them. Depending on the species of fish, fish can retain memories from between a few days to several years!

A great example of this is salmon returning to the place they were born to spawn. Scientists believe they are able to do this by biologically reading the earth’s magnetic field like a personal compass.

However, it still requires a pretty powerful memory to remember their own birth site!

Another example shows fish learning to navigate an underwater maze to find food, similar to mazes set up for rats to study cognitive function. After training, goldfish were able to remember the path needed to be taken to reach the food, displaying impressive memory skills. 

Carp anglers have discovered the distinct memory capabilities of carp while fishing. Both anglers and researchers say that carp that have been caught once and tossed back are significantly less likely to be caught again. 

Learning New Tricks

Fish are so intelligent that they can also learn cool tricks. One famous example of a talented goldfish was Albert Einstein, a goldfish who went viral for learning how to push a tiny soccer ball into an underwater goal.

According to his owner, Einstein could also swim through hoops, travel through tunnels, and carry tiny balls from the floor of his aquarium to the surface for his owner. 

Other goldfish owners have done similarly. One of the most simple tricks taught to goldfish is to eat from their owner’s hand. 

Owners can also easily teach their goldfish the hoop trick. 

By placing a hoop into the tank and holding a pinch of food on one side of it, you can attract your fish to go through the hoop. With regular practice, your goldfish will soon stop trying to go around the hoop and will go through the hoop regularly. 

By using food to reward your goldfish, they can learn many tricks just like Albert Einstein. If fish didn’t have a brain, they certainly wouldn’t be able to do all that!

Natural Instincts and Behaviors

Without a brain, fish wouldn’t be able to engage in any of their normal behaviors in nature. Even communicating with one another would be impossible for fish, which would cause some pretty big problems when it comes to feeding and mating. 

Red Sea Clownfish, for example, mate for life. Even in experiments that removed one mate from the home anemone, the other still recognized and remembered their mate after nearly a month apart. 

Without a brain, these clownfish would never be able to remember and recognize each other long enough to mate for life!

Wrasses are also capable of using tools in the wild. This family of fish will find a clam or scallop to eat, take it to a nearby rock, and use the rock as an anvil to smash the clam open for consumption. 

Besides eating, fish can construct as well. The Japanese Pufferfish is an excellent example of this.

The male Japanese Pufferfish will spend 24 hours per day for an entire week during mating season creating a sand mound to attract a female. The cognitive ability to design and implement this structure is one of the most fascinating discoveries of the capabilities of fish. 

Conclusion

Thanks to science, we can see that fish definitely have brains! Not only that, but fish can also use their brains for some pretty cool things. 

The next time someone asks you if fish have brains, be sure to share with them some of the things fish do with their brains. Then, amaze them with your knowledge about fish with the biggest brains!

If you have any other questions about fish, feel free to leave a comment below or send us a message. We’re always looking for new topics to cover in our upcoming articles. 

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