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How Smart are Fish? An Interview with Maria Martina Quaggiotto PhD



The normal perception of fish in the human psyche is that of unintelligent and unfeeling. I know from a lifetime of diving and watching marine species that they are not at all stupid, especially fish.

Maria Martina Quaggiotto from the University of Glasgow has a PhD in Ecology and Environmental Biology and with Professor Felicity Huntingford has produced a wonderful interactive e-learning presentation called How Smart are Fish‘, based on tireless research by generations of fish behavioural biologists on fish cognition (“smartness of fish”), both for science and general education. The programme covers many aspects of smart fish, such as tool use, memory, learning, social interaction and cooperation.

Jeff: Hi Martina. Thanks for talking to us about your research into fish intelligence. As we systematically fish our oceans bare and treat fish species as mindless automatons, I was heartened to read your findings and look at the resulting educational programme available on the web.

First of all I would like to congratulate you on a thoroughly comprehensive and informative learning programme. Before we talk about your findings could you tell me how you first became interested in the marine world and especially the smartness and cognitive abilities of fish and determining their level of smartness?

Martina: Since I was little, I used to spend my summer holidays at the seaside in Croatia. My brother and I spent most of our time in the water swimming and snorkelling. I have always been fascinated by all the sea creatures I could find on the sea bottom or attached to rocks. I remember that the beadlet anemones (in Italian “sea tomatoes”) were always catching my eyes and I used to stare at them while either feeding with their tentacles or completely closed depending on the tide. As marine biologist I studied the anatomy and ecology of fish during my Masters, but somehow I have never been taught of what these animals are capable of. I started learning about their cognitive capabilities only when I met Prof Felicity Huntingford and started working with her. I still remember the sense of astonishment when she introduced me to the topic explaining to me how fish are able to distinguish weaker and stronger conspecific – so that they can hang out with the weaker to avoid potential aggression – making deduction equivalent to what humans called transitive inference! I couldn’t believe it!!

Jeff: Did you feel that fish were smart beings before starting your research or did that come to you later?

Martina: I believe I realised that fish were smart enough to outsmart me already when I was a kid. I was around 10 years old and I used to go fishing together with the men of my family armed of my little rod at the sport lake outside my home town. I was quite good at it! My best skill was applying the worm to the hook, so that it couldn’t be seen by the fish at all. This was my secret for successful fishing! I think that while perfecting this technique of mine I was actually recognising for the first time that fish could be smart enough to avoid hooks! However, I have to admit that only now I completely appreciate the wide range of capabilities of fish. My work with Felicity on fish smartness definitely opened up a world of which I did not know much. Fish, in fact, not only can avoid hooks, but they can create mental map of their surroundings, make things like elaborated nests, using tools to feed, learning from each other and even collaborate to inspect a predator.

Jeff: What has been the most surprising thing you have learnt or discovered during your work?

Martina: The most incredible think I learnt is that archerfish can recognise human faces!  Archerfish are fish living in brackish waters of estuaries and mangroves, well-known for its abilities in shooting at terrestrial insects living on plants by spitting a powerful jet of water making them falling onto the water surface where the archerfish can reach and eat them. In the laboratory, scientists presented archerfish with two images on an overhead screen, each showing a different human face, one of which (say face X) was the same in all trials, but not always on the same screen. A food pellet was released from above if and only if the fish spat not at face X, but at the one it was paired with. Fish were able to discriminate between 44 faces (on average making more than 70% correct choices) by communicating their choice to scientists by spitting on them!

Scientists used to think that only animals whose brain includes the neocortex or a neocortex-like structure (as found in birds) were capable of recognising human faces, but it is now certain that also archerfish have this capacity! So, check out divers.. fish know who you are!

Jeff: You define the term smart as being able to learn, the ability to appraise and integrate information and make context- dependent decisions. After all your work are you able to confidently say that fish are truly smart?

Martina: I would confidently say that science demonstrated that, as a group, fish are able of all the main kinds of learning that have been reported in mammals and that their memories are long enough for the purpose. For instance, fish may forget how to handle a particular type of prey if this ceases to be available, but they can remember forever the bad experience of encountering a predator. The cognitive abilities of fish, however, can vary depending on the surrounding environment where they live. For instance, intertidal rock pool gobies when disturbed in a particular rock pool would usually safely jump from a rock pool to either to the open sea or to a safer pool, without stranding. This is possible because during high tide rocky gobies memorise landmarks associated with the various potential rock pools in their home ranges. Gobies from the sandy habitat, on the other hand, are not as good as their counterparts from the rocky habitat at using learned landmarks to escape the falling tide. This doesn’t mean that rocky gobies are smart whereas sandy gobies are not. It indicates, instead, that living in a complex environment place demands on the ability to move about efficiently, sometimes favouring the ability to form and use mental maps.

Jeff: As the majority of people assume fish are not at all smart, did you find your research at all hampered by people who thought it was a waste of time and resources?

 Martina: Fortunately not!. I believe that the majority of people, whether they agree or not on fish being smart, still respect scientifically proven findings and therefore would not react negatively to this research. Said that, I think we created a lot of interest in this topic, instead… Of course, we met few sceptical people who argued that some fish are not smart at all. Anglers, practising catch and release, for instance, may experience some specimens getting hooked consecutive times, showing little learning from the unpleasant experience. As scientist, I can argue that there is always variation among fish in how quickly they learn. Even in scientific experiments some individuals are fast-learners, some others take numerous trials to learn, some others cannot learn after a set number of trials. Anglers’ knowledge may be anecdotal, but it is often based on years of experience and hours of observation.. It is important to take it seriously and test it scientifically, as it can be revealed to be true.

Jeff: Tool use is a very interesting aspect of fish behaviour. As this takes place underwater it will be mainly divers that are able to be witnesses. Did you seek cooperation from divers and what was their general reaction to your work?

Martina: One of our examples of tool use in fish has been witnessed in the first place by a diver.  He took some extraordinary photos of a black spot tuskfish using a rock as an anvil to open a cockle shell while diving in the Great Barrier Reef (Australia). The photographs show how the fish first transported the shell with its mouth towards a natural anvil, then, moving sideways, hit the shell against the stone on both sides, smashing it and finally eating its content. Using stones as anvils is a recognised form of tool use in primates and birds, and presumably requires similar cognitive capabilities when performed by fish.  Such behaviours are not uncommon, but as it takes place underwater, it is rarely observed in the wild. Who better than a diver to witness this behaviour? Cooperation from divers is essential to reveal smart behaviour of fish! In fact, the documentation of the Australian diver was published in a scientific journal.

And yes!, definitely I needed the support of divers when I was preparing the e-learning presentation. I asked for their help in order to enrich the online resource with the right underwater footage and photos of fish, possibly demonstrating their capabilities. One of my favourite videos appearing in the e-learning presentation is the one showing the cooperative and Machiavellian behaviour of the cleaner wrasse with its clients. It was taken by a friend of mine while diving in Egypt and now it is included in the section “Cooperation between species” of our online resource.

My impression is that divers were among the most supportive people of our project when it came out. Because divers spend much time underwater observing marine creatures, they develop a greater understanding of fish behaviour than other people who do not dive. I believe that they could confirm that fish can be smart without hesitation!

Jeff: What was the most surprising use of tools you came across?

Martina: In my opinion the most surprising tool use in fish is the one that scientists struggle to define.. in other words, the playing behaviour by using objects. Burghardt and colleagues (2015) observed an unusual behaviour adopted by three male cichlids held in aquaria. These fish repeatedly interacted with a floating thermometer, nudging it with their snouts, waiting for it to return in its vertical position, and then repeating this response. He and his colleagues argue that this behaviour could be considered to be play because 1) did not have any clear, complete function; 2) was spontaneous or voluntary and apparently pleasurable; 3) was different in detailed form from similar behaviour performed ’for real’; 4) was repetitive, but not abnormal and; 5) was initiated only in the absence of stress. For a long time, play was thought to be confined to warm blooded animals, including mammals such as primates, dogs, cats and rats, and some birds, but it has now been recognised in fish as well. This discovery gave light to another amazing aspect of fish behaviour so far unknown.

Jeff: There are so many aspects to your research and conclusions that I could ask you questions all day, but for the sake of time can I ask you if there has been any positive progression directly due to your work in the way we treat fish?

Martina: The main goal of our e-learning presentation is to overturn the prevailing view that fish lack the machinery for smartness, having poor learning capacity and a very short memory span. For instance, it is still common using the words“goldfish memory” when referring to forget what happened in the last 15 seconds. Even in the pixar movies Finding Nemo and Finding Dory the famous Pacific regal blue tang Dory is depicted as a very forgetful fish. The positive progression due to our work would be seeing this view changing thanks to the scientific evidence we provided in our online resource. The sooner people realise that this view is inaccurate, the sooner these animals will be considered worthy of conservation by the general public. In this way we hope that more attention will be devoted to the conservation of fish.

Our e-learning presentation on smartness of fish has been visited online already thousands of times, meaning that our words are out there. However, this is not enough. We really think that you, divers, could also do your part by spreading the truth about how smart fish are as well. Unlike most of the general public, you are not alienated from this unknown underwater world and its inhabitants. Thus, you can be fish ambassadors together with scientists and (the majority of) anglers!

 Jeff: Is your work on smart fish now complete or is there still much to do?

Martina: This work is going on since 2016 when Prof Huntingford was nominated Buckland Professor of Fisheries. At that time we ran a series of lectures for the general public entitled “How smart are fish? Integrating what scientists and fishers know” in the UK and Ireland, where the scientific knowledge was placed side by side with the knowledge of fishers. Because of the expressed interest in the topic by the general public we decided to work on the e-learning presentation. Now, that this is completed, we are working on the scientific papers. So, going back to your questions, Yes, we have still work to do! We are currently finalising a review about fish cognition in both the social and non-social contexts illustrating how smartness can vary between and within species and how this relates to differences in brain structure. So, please, if you are interested in the topic, stay tuned!

On the educational point of view, we would love to increase further the impact of the e-learning presentation by transforming it into a Massive Open Online Course (MOOC) available for anyone to enrol. But this is still work in progress!

Jeff: Ultimately this work has implications on how we treat fish in the future, especially in the commercial fishing industry as well as angling and spear fishing. Can I have a final thought from you on this?

Martina: The information we collated on how the smartness of fish impacts on fisheries emphasises just how important this is for the management and conservation of fish populations. Considering smartness of fish within strategic plans of conservation may, in fact, enhance their effectiveness. Marine reserves, for instance, should be planned taking into account existing topographic landmarks so that fish can use them to create mental maps and navigate within their home range. Protected areas, then, should consider that wariness of fish decreases when inside, making them more vulnerable to fishers when going outside. Such unwary behaviour could be detrimental for fish conservation, reducing the overall value of a marine protected area. As another example, we know that different kinds of fishing gear capture selectively fish with different behavioural profiles (more or less easily scared, faster or slower at learning, for example). This means that, over time, the process of fishing itself may alter the behavioural profile of exploited fish stocks, which may well be important for sustainability of commercial fisheries. Finally, successful restocking programmes for both marine and freshwater species should apply environmental enrichment during rearing of fish in captivity to develop smarter fish to be released in the wild. There is so much that we can do!, but let’s start to respect fish for what they are.. smart creatures!!

Thank you very much Jeff for dedicating one of your amazing interviews to explain better our work on the smartness of fish! We hope that the readers of Scubaverse enjoyed it.

Jeff: Thank you Martina

You can watch the “How Smart are Fish?” interactive e-learning presentation by clicking here.

Jeff Goodman is the Editor-at-Large for with responsibility for conservation and underwater videography. Jeff is an award-winning TV wildlife and underwater cameraman and film maker who lives in Cornwall, UK. With over 10,000 dives to his credit he has dived in many different environments around the world.

Marine Life & Conservation Blogs

Top Destinations to dive with Manta Rays



In their mission to create a billion Torchbearers to explore and protect the ocean, PADI is encouraging divers to seek adventure and experience first-hand the vital eco-systems below the surface of the ocean.

To further raise awareness of this mission on International Manta Ray Day (17 September 2021), PADI has rounded up the top destinations in the world that are currently open to divers.

Machadilla National Park, Isla de la Plata, Ecuador

Diving in Ecuador offers a special paradise for scuba divers, in which the chance of encountering marine species nowhere else on earth is extremely high due to the heavy currents and nutrient rich waters. And for those keen to dive with manta rays, head out with PADI 5 Star Dive Center Exploramar Diving, or PADI 5 Star Dive Center Mares Ecuador here they take divers out to Machadilla National Park in Isla de la Plata for a chance to greet these graceful creatures every July to September.

Find out more with PADI’s Dive Guide for Ecuador

Kona, Big Island, Hawaii

Hawaii’s volcanic origins and isolated geographical location makes for a whirlwind of scuba diving encounters underwater, with manta ray encounters being likely all year long. For those looking for an extra special experience,  PADI 5 Star Dive Center Jack’s Diving Locker offers a manta ray night dive and a PADI Distinctive Specialty Course called Manta Ray Diver, which covers everything from the manta ray anatomy to cleaning habits, reproduction and how to identify individual rays in the local population.

Find out more with PADI’s Dive Guide for Hawaii

Bryon Bay, Australia

For those who are currently in Australia, they can have their backyard manta ray encounter with PADI 5 Star Dive Center Sundive Byron Bay. The summer months of December to May bring manta rays to the nearby Julia Rocks Marine Reserve, which National Geographic once acknowledged as one of the top 20 dives in the world.

Find out more with PADI’s Dive Guide for Australia

Manta Point, Nusa Penida, Bali

The name speaks for itself. Manta Point in Bali is a haven for manta rays all year long, with the best time to see them being from April to May. PADI 5 Star Dive Center and Resort  Scuba Junkie Penida  offers the ultimate manta ray diving experience in the area, adding coral dives and drift dives to the day’s adventure.

Find out more with PADI’ Dive Guide for Bali

Komodo National Park, Labuan Bajo, Indonesia

One of Indonesia’s most famous diving destinations is also one of the best places to dive with manta rays! PADI 5 Star Dive Resort Blue Marlin Komodo is the perfect place for a manta ray holiday, where divers can stay at the dive resort while getting their PADI Open Water Diver certification and then hop aboard their dive vessel for a day of diving out at sea with manta rays!

Find out more with PADI’s Dive Guide for Indonesia

Six Senses Manta Point, Laamu Atoll, Maldives

Crystal clear warm waters, white sandy beaches and manta rays—PADI 5 Star Dive Resort Six Senses Laamu offers the ultimate luxurious manta ray holiday. As the only dive resort in the Laamu Atoll, divers of all levels will have extremely personable encounters with manta rays every month of the year in this world-class diving area.  There are also more than 180 PADI Dive Centers and Resorts in the Maldives that can take divers out to have a manta ray encounter.

Find out more with PADI’s Dive Guide for the Maldives

Azores, Portugal

The islands that make up the Azores off the coast of Portugal are one of the most diverse for marine life. One  specific type of manta rays known as the Mobula birostris is known tohang out in large groups around the island of St. Maria between June and October, with PADI 5 Star Haliotis Dive Center offering guided boat trips to the island.

Find out more with PADI’s Dive Guide for Portugal

Diving with whale sharks and manta rays can make a difference in protecting these incredible species for future generations – dive tourism encourages protection from local communities and governments. But its important to always adhere to local guidelines and best practices to ensure these creatures’ well-being is always at the forefront. PADI dive operators understand the importance of using the proper equipment, the time of day to dive with sharks, and the maximum number of operators that should be on the water at any given time. To learn more about responsible shark and ray tourism and other ways you can support the protection of these incredible animals, visit

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Marine Life & Conservation Blogs

Creature Feature: Manta Rays



In this series, the Shark Trust will be sharing amazing facts about different species of sharks and what you can do to help protect them.

This month they’re showcasing the largest rays in the world. Made up of 2 different species, these captivating giants are highly intelligent. And, come in a range of unusual colours!

The word ‘manta’ is Spanish for blanket or cloak, which perfectly describes the body-shape of a manta ray. These enormous, flat, diamond-shaped animals, have wingspans stretching up to 7m wide and can weigh up to 1,350kg.

Mantas also have 2 horns at the front of their head, giving them the nickname ‘devil fish’. But there’s nothing devilish about these gentle giants. Or their close cousins the devil rays, who often get confused for mantas. Both, use their ‘horns’ (or cephalic fins) during feeding to scoop up tiny plants and animals in the water. Similar to how we use a spoon to eat soup. Their cephalic fins may also play a role in sensing their environment and during social interactions.

Just like the Basking and Whale Shark, manta rays are filter feeders. Swimming with their mouths wide open, they suck in huge volumes of water – rich in zooplankton. Their tiny prey is then filtered through gill plates that line their mouth. Sadly, these gill plates are highly sought after in the Chinese medicinal trade, which has led to mantas being heavily over-fished.

As any diver can attest, seeing a manta in the wild is a pure delight. Their elegance and grace in the water is unrivaled. Particularly at feeding time. Mantas need to keep moving to breathe, so individuals will perform multiple somersaults to stay in a single spot where there’s lots of food. Like a perfectly orchestrated dance, mantas will also follow each other in a circle to chain-feed. Their movements expertly creating a vortex that traps their prey inside.

Manta Rays live in tropical, subtropical, and temperate waters around the world. They tend to live on their own or in small groups. But will often gather in large groups to feed. Hotspots for this feeding behaviour include the Bahamas, Fiji, Indonesia, Thailand, Spain and the Maldives. And aggregations are known as a squadron of manta ray.

In 2008, scientists discovered that the Manta Ray, which was once thought of as a single species, was in fact two different species. The Giant Oceanic Manta Ray (Mobula birostris) and the much smaller Reef Manta Ray (Mobula alfredi). Both species were formerly classified under the separate genus Manta. But following genetic testing in 2017, scientists discovered they were more closely related to devil rays (genus Mobula) than previously thought and reclassified them as such.

The Giant Manta is widespread, spending most of their time far from land in open ocean. While the Reef Manta tends to prefer the warmer coastal waters of the Indo-Pacific. Fully grown, the wingspan of a Giant Manta can reach up to 7m (typically 4.5m). While the largest wingspan for a Reef Manta is 5m (typically 3-3.5m). Both are dark in colour on top with a pattern of white lines. On the Giant Manta the white lines form a T shape, while on the Reef Manta they form a Y shape.

We can also identify each individual manta by their unique markings. Found on the underside of their body (between the gills and on their bellies), these act just like a human fingerprint. Enabling scientists to use photo-ID to discover more about them.

Manta Rays regularly visit cleaning stations, like many other marine animals, often returning to the same spot. Here smaller animals groom them, removing pesky parasites and dead skin. These spa trips to the coral reef provide researchers with the perfect opportunity to photograph and study them in the wild.

In Raja Ampat, researchers have discovered an unusual group of Reef Mantas, affectionately known as the ninja warriors. This area has the highest percentage of melanistic (black) Reef Mantas in the world. Usually melanistic mantas comprise around 10% of a population, but here they represent 40%. This genetic trait is inherited and doesn’t appear to affect their survival rate.

If you visit the Great Barrier Reef, you may witness an even more astounding sight…

A 3m male Reef Manta named ‘Inspector Clouseau’, who also happens to be bright PINK! Big thanks to Kristian Laine Photography for providing the incredible photo above.

The Inspector is the only known pink manta in the world. His rosy hue is believed to be the result of a condition called erythrism – a genetic mutation in melanin production. Again, this doesn’t seem to impact his survival. Indeed, he’s been spotted a handful of times since his first debut in 2015, so is doing well.

Highly intelligent, these majestic animals have the largest brain to body weight ratio of any fish. Studies suggest they have high cognitive function – similar to dolphins, primates and elephants – and excellent long-term memory.

Due to their large size, adult mantas don’t have many natural predators. Although, larger sharks and orca have been known to prey on them. Yet, the biggest threat they face comes from humans. Due to their low reproductive rate mantas are incredibly vulnerable to over-fishing.

These long-living animals are thought to live up to 50 years. Giving birth every 4-5 years, they’ll only produce between 4-7 pups during their lifetime.


  • SCIENTIFIC NAME: Mobula birostris
  • FAMILY: Mobulidae (Manta & Devil Rays)
  • DIET: Zooplankton, krill & small fish.
  • DISTRIBUTION: Worldwide in tropical and temperate waters. Found from the surface to depths of 1,000m.
  • HABITAT: Spends long periods of time in the open ocean. Visits shallow coastal waters near coral and rocky reefs.


  • SCIENTIFIC NAME: Mobula alfredi
  • FAMILY: Mobulidae (Manta & Devil Rays)
  • DIET: Zooplankton, krill & small fish.
  • DISTRIBUTION: Tropical and sub-tropical waters of the Indian and Pacific Ocean. Found from the surface to depths of 432m.
  • HABITAT: Shallow coastal waters near coral and rocky reefs. Moves into deeper waters at night to feed.

Header Image: Frogfish Photography

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