5 Incredible Fish Behaviors That Show Just How Intelligent They Really Are

Editor’s note: This Care2 favorite was originally posted on July 4, 2015. Enjoy! 

The vast majority of people are under the illusion that fish are unintelligent and incapable of feeling pain in the same way as mammals. That misconception contributes to a care-free attitude toward the capture and murder of billions of fish each year for food.

An incredible study of fish behavior by a team of marine biologists led by Redouan Bshary proves once and for all just how clever fish really are. Here are five complex behaviors which he observed and documented:

1. Mutual Cooperation

There are numerous instances of mutual cooperation in the animal kingdom. The Great Barrier Reef is a hive of activity, involving thousands of different marine species, many of whom have learnt to cooperate with each other for mutual benefit.

The most impressive of these systems is the “cleaning stations” where larger fish will come and let the smaller “cleaner fish” eat the tiny parasites off them. This means food for the cleaner fish and fewer parasites for the larger ones.

2. Cheating the System

The complexity of the activities observed at the cleaning stations was astonishing, and Bshary watched the cleaner fish alter their behavior depending on how busy the cleaning station was and how many other cleaner fish were around to service their “clients.”

The cleaner fish prefer the taste of the nutritious protective mucus which covers the skin, and they will take the occasional bite. When the larger fish are bitten they thrash around, but would usually put up with the occasional bite or two. However, if there are lots of other cleaner fish to choose from, they will go elsewhere for a cleaning.

The cleaner fish have learned that they can cheat the system and take more bites of the mucus depending on how many other potential clients or cleaning fish were around, as they can get away with it if there is nobody else to clean them.

3. Hunting Partners

Numerous hunting partnerships have been observed between some of the top predators on the reef, groupers and morays. Normally these fish would be expected to be in competition together, but have worked out a hunting system which is mutually beneficial.

One of the fish swims into the reef and flushes out their prey into the open water, or an enclosed channel, where they become an easy target for all to eat.

4. Body Language Signaling

The hunting fish use sophisticated body language communications to synchronize their attacks, with a nod of the head being the final cue to action.

This kind of complex communication is not specific to fish found on the coral reef. It is observed in fish populations around the world, the most visually impressive of which is the synchronized schooling of thousands of tuna, who swirl around to confuse predators.

5. Identifying Fast Food Options

One of the most impressive observations made by Redouan Bshary was that cleaner fish had cognitive processing skills greater than those observed by primates, and even his 4-year-old daughter.

A food plate test was set up to see if the fish would learn to recognize that one plate of food would always remain in place, and another would only stay for a short amount of time before disappearing, and that they needed to eat from the temporary plate first.

The cleaner fish excelled, and showed their superior perception by very quickly learning to eat from the plate which would soon disappear, before eating from the stationary one. They even worked this out under a number of more in-depth tests, such as with different colored plates.

In contrast, the primates who had previously tried this test took much longer to learn how to adapt to the system, and Bshary’s 4-year-old daughter never once worked it out, after more than 100 attempts.

Perceiving the World through New Eyes

As humans, we have developed a very self-centric view of the world, where we judge all other species by our own perception of them. For us to develop into a more compassionate society, which is not responsible for the murder of billions of animals each year, we must learn to understand and respect each and every animal on the planet for who they are.

Photo Credit: yu tang/Unsplash


Melania P
Melania P8 months ago

Nature and animals are so amazing, there is so much we don't know yet! I thank we have science that shows us what we thought it'd never be possible!

Marie W
Marie W9 months ago

Thanks for sharing.

Virgene L
Virgene Labout a year ago

Well, I am surprised, but guess I shouldn't be. Fish have been swimming and existing for longer than humans. They had to have good abilities to do that! Thanks for the interesting information.

Philippa P
Philippa Powersabout a year ago

Fish are more intelligent than we give them credit for.

Elaine W
Elaine Wabout a year ago

Before reading this post, I was unaware of the scope of fishy smarts. ;)

Chris Ringgold
Chris Ringgoldabout a year ago

Wow! These Fishes are truly Geniuses.

Richard A
Richard Aabout a year ago

Thank you for this article.

Sonia M
Sonia Mabout a year ago

Interesting article thanks for sharing

caroline lord
caroline lordabout a year ago

Absolutely; never understood those 'vegetarians' who eat fish! or the drs surgeries in which one encounters too many depressed and miserable fish crammed into a miniscule tank

Marija M
Marija Mabout a year ago