8 Smartest Fish

goldfish tanks
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Written by Sarah Psaradelis

Updated: July 3, 2023

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When people think of a smart animal, a fish rarely comes to mind. But fish can be smart too, in ways that might surprise you. Aside from their amazing physical adaptions to life underwater, fish are intelligent animals. They can even be trained, learn routines, and remember faces with great cognitive abilities. Most people do not associate intelligence with fish. However, research is proving fish to be smarter than we give them credit for.

Picture graph of 8 Smartest Fish
Observations and lab studies have revealed an unexpected intelligence among fish.

Remember, “Everybody’s a genius, but if you judge a fish by its ability to climb a tree, it will live its whole life believing that it is stupid.” – Unknown

Fish Intelligence

Clownfish in a sea anemone.

Recent research gives us a new understanding of fish – these animals are smart, and can feel, and experience emotion!

©Alex Stemmers/Shutterstock.com

Fish are complex creatures that each have their own levels of intelligence depending on their species and survival responses. For example, some fish species have evolved a smart feeding response where they utilize tools or body parts to catch prey. Whereas other fish are purely clever and show high levels of intelligence in studies and interactions with humans.

Other fish such as goldfish have shown that their memories are excellent, and they can remember things for years. Fish can learn from one another, pick up on social cues, and some are even self-aware. Many fish show intelligent behavior, unique methods of communication, and even defense mechanisms.

goldfish in aquarium

Contrary to popular opinion, goldfish have excellent memories.

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Let’s look at eight of the smartest fish out there:

1. Tiger Oscar Fish

Oscar fish swimming in dark water

Oscars are well known for being aggressive aquarium fish, but they are also intelligent and connect with their human owners.


The Tiger Oscar is an African cichlid and is known to be a highly intelligent fish in the aquarium hobby. Oscars are fondly known by their owners as “water dogs” because they are interactive fish that act with purpose. Oscar fish can recognize their owner’s faces and movements, especially when it comes to detecting their next meal.

Although Oscar fish have a reputation for being aggressive with tankmates, they couldn’t be more playful and affectionate with humans, showing they can form bonds with people.

The Oscar’s human-like traits have earned this fish a spot as one of the most intelligent freshwater fish, mainly because their domestication has led people to regularly watch and interact with them to see just how smart they can be.

2. Manta Ray

manta ray swimming close to ocean floor

Manta rays can grow up to 25 feet wide.


The Manta ray has the largest brain-to-body weight ratio out of all documented fish species. They might not be the biggest fish in the sea, but their large brains are the reason they are so smart. These big-brained fish are believed to be quite self-aware and have developed areas for communication, problem-solving, and learning.

Manta rays are known to be great navigators and can travel long distances underwater with excellent navigation skills. They have been known to swim to familiar diving teams where they know they will get fed and interact with humans.

A 2016 experiment by the University of Colorado found that Manta rays would react to their reflections in mirrors. Their behavior showed that they recognized the reflection as themselves and not another Manta ray.

This experiment showed that Manta rays have the self-awareness that many other fish species lack.

3. Galaxias

Galaxias maculatus - A plateful of whitebait, or inanga, a delicacy in New Zealand, recently thawed and about to be cooked

Galaxids, small freshwater fish, have a length of 1.6-5.9 inches.

©Philip Armitage/Shutterstock.com

Rats are commonly used in lab trials to further understand how animals can learn. However, the Galaxias fish might be smarter than a rat, according to lab experiments. An experiment showed that these fish might be capable of learning certain routines faster than a rat.

The time the Galaxias took for time-place learning was five days less than a rat needed. Galaxias fish learned this method in only 14 days, while rats needed 19 days. This proves that Galaxias fish have the cognitive ability to learn new things quickly.

4. Elephant-nose Fish

Elephant Nose Fish, gnathonemus petersii



-nose fish finds its prey by using electrolocation.


The Elephant-nose fish has one of the largest body-to-brain ratios in comparison to all known invertebrates. These fish use a whopping 60% of their body’s oxygen in their large brains.

Aside from a good oxygen flow to their brain, Elephant-nose fish brains take up a greater percentage of their body weight than humans, which has landed them a spot as one of the smartest fish species.

If that wasn’t enough, Elephant-nose fish also have a mild electric field sort of like an electric eel, but less powerful. Using electrolocation and electroreceptors around their bodies, elephant-nose fish can detect prey, find food, and navigate in dark or murky waters to find a mate. This is truly a smart and fascinating fish!

5. Goldfish

Fantail Goldfish in aquarium with green plants, and stones.

Goldfish are omnivores that eat plants, insects, and much more.


The goldfish is a popular freshwater fish in the aquarium hobby and was previously believed to only have a 3-second memory. This couldn’t be more untrue, as goldfish have memories that can last for weeks, months, and even years.

This is backed up by science, according to Culum Brown, a fish cognition expert at Macquarie University in Australia. Goldfish are often used as ‘learning fishes’ because of their great memory and ability to learn new things.

Sadly, goldfish are often misunderstood and kept in small bowls or aquariums where they do not have enough space and entertainment to prove how smart they can really be. Goldfish can learn how to repeat tasks that they were taught months or even years ago and can remember their owner’s faces after time has passed.

6. Channel Catfish

Channel catfish

The Channel Catfish has excellent senses of taste and smell.

©Aleron Val/Shutterstock.com

Countless research studies have shown that fish can retain information for years and remember things quite well. This is especially true for Channel catfish, who have been found to recognize the voice that calls them for food even after hearing the voice five years ago, which is quite impressive. This further proves that fish can have a good memory.

7. Crimson-Spotted Rainbow Fish

Redfin Dwarf Rainbowfish Aquarium fish  Melanotaenia maccullochi

Many species of rainbowfish are sought after for aquariums.


Fish can form cognitive maps in their minds, often to avoid going to the same place where they had a bad experience, or to remember landmarks for navigation underwater.

The Crimson-spotted rainbow fish is one example of a fish that can be taught and remember in certain techniques. This fish learned how to escape from a trawl by swimming through a specific hole in the center, and could remember this exact technique 11 months later.

This showed that the Crimson-spotted rainbow fish was able to integrate an experience in its mind and form a response from previous teachings to avoid and escape a situation that was not ideal.

8. Archerfish

Animals that Eat Insects – Banded Archerfish

Banded archerfish look outside the water for food such as insects, larvae, and worms.

©Henner Damke/Shutterstock.com

The Archerfish is an example of a smart fish species that can use tools to make life easier, especially when it comes to feeding. Archerfish squirt jets of water out to insects on plants, and they can recognize the size of the prey and adjust the size of their squirts accordingly.

Archerfish do this to knock the insects into the water, where they can easily eat them. These fish have also been known to have such good accuracy that they can even shoot moving insects and rarely miss them.

Summary of the 8 Smartest Fish

Several of these smart fish would make excellent pets:

FishIntelligence Indicators
Tiger Oscar FishCan recognize its owner’s face and movements and form bonds with people.
Manta RayHave a large brain; can recognize themselves in a mirror; self-aware and have developed areas for communication, problem-solving, and learning.
GalaxiasCapable of learning certain routines faster than a rat.
Elephant-nose FishOne of the largest body-to-brain ratios compared to all known invertebrates; use 60% of body oxygen in the large brain.
GoldfishHave memories that can last for weeks, months, or longer; can learn new things.
Channel CatfishCan retain information for years and recognize a voice.
Crimson-Spotted Rainbow FishCan form cognitive maps in their minds and retain certain techniques.
ArcherfishCan use tools to make life easier; can recognize the size of the prey and adjust the catch accordingly.

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About the Author

Sarah is a writer at A-Z Animals primarily covering aquatic pets, rodents, arachnids, and reptiles. Sarah has over 3 years of experience in writing and researching various animal topics. She is currently working towards furthering her studies in the animal field. A resident of South Africa, Sarah enjoys writing alongside her pets and almost always has her rats perched on her shoulders.

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