Fish can exhibit behaviors as intricate as those of humans
Along the Portuguese coast, a quiet scientific provocation takes shape: an exhibition in Cascais invites the public to reconsider the inner lives of fish, those creatures long dismissed as simple and reflexive. Born from years of research at the University of Lisbon's MARE center, the show asks whether intelligence is a ladder with humans at the top — or something far more varied and surprising. From June through September, the Museu do Mar Rei D. Carlos becomes a space where neuroscience, ecology, and humility converge.
- A persistent cultural myth — that fish are little more than living reflexes — is the target this exhibition has spent years preparing to dismantle.
- Seven illustrated panels, 3D brain models, and documentary footage compress complex behavioral science into something a curious visitor can walk through in an afternoon.
- The side-by-side comparison of fish and mammal neural architecture is the exhibition's quiet provocation: the differences are real, but so are the unexpected similarities.
- Researchers worked across two fronts — controlled laboratory conditions at the Guia Maritime Laboratory and open coastal field studies — to ensure their findings hold in both precision and reality.
- Backed by municipal and international foundations, the June 11th opening is free, signaling that this science is meant for everyone, not just those already convinced.
On June 11th, the Museu do Mar Rei D. Carlos in Cascais opens its doors to an exhibition that asks visitors to rethink what they know about fish. Titled "Fish Intelligence: Behavioral Complexity in an Underwater World," the show is the product of years of research by MARE — the Center for Marine Sciences and the Environment — based at the University of Lisbon's Faculty of Sciences. It runs through mid-September, offering seven panels of findings illustrated by biologist and artist Lia Neves.
The driving force behind the exhibition is José Ricardo Paula, a principal investigator at MARE's Laboratory of Behavioral Complexity. His team's work challenges a stubborn assumption: that fish are simple, nearly automatic in their responses. The research reveals otherwise. Fish can solve problems, recognize individual faces, use tools, and respond to their environments in ways that are neither reflexive nor predictable — what scientists call behavioral complexity.
Visitors move through the exhibition as through an argument being built. A documentary by Vasco Pissarra captures both laboratory experiments and coastal field observations. Three-dimensional brain models place fish neural structures beside those of other animals, making visible the unexpected overlaps. The effect is to reframe intelligence not as a single hierarchy, but as a landscape of different cognitive strategies shaped by evolution and environment.
The exhibition draws on work conducted both in MARE's Maritime Laboratory in Guia and in natural habitats — a dual method that lends the findings both rigor and relevance. It has received support from the Cascais Municipal Council, the Luso-American Foundation for Development, the "La Caixa" Foundation, and the Foundation for Science and Technology. The inaugural session is free, a deliberate gesture toward public access.
What the exhibition ultimately offers is a portrait of fish as beings with inner lives — capable of learning, remembering, and choosing. The claim is not that fish think as humans do, but that the distance between the two is narrower, and more worth examining, than most people have ever been invited to consider.
On June 11th, the doors open at the Museu do Mar Rei D. Carlos in Cascais to an exhibition that asks visitors to reconsider everything they thought they knew about fish. The show, titled "Fish Intelligence: Behavioral Complexity in an Underwater World," emerges from years of research conducted by MARE—the Center for Marine Sciences and the Environment—a research hub housed within the Faculty of Sciences at the University of Lisbon. For three months, from mid-June through mid-September, the public will have the chance to walk through seven panels of scientific findings, each accompanied by original illustrations created specifically for this project by biologist and illustrator Lia Neves.
The exhibition is the work of José Ricardo Paula, a principal investigator at MARE's Laboratory of Behavioral Complexity and a professor at the university. Paula and his team have spent years studying how fish think, learn, and interact—work that challenges a persistent cultural assumption: that fish are simple creatures, nearly reflexive in their responses to the world around them. The research tells a different story. Fish, it turns out, possess cognitive abilities that sometimes mirror those of humans. They can solve problems, recognize individual faces, use tools, and demonstrate what researchers call behavioral complexity—the capacity to respond to their environment in ways that are neither automatic nor predictable.
The exhibition itself is structured as a journey through this emerging science. Visitors will encounter a documentary filmed by Vasco Pissarra that captures laboratory experiments and field observations conducted in coastal zones. They will see three-dimensional models of fish brains positioned alongside brains from other animal groups, revealing unexpected similarities in neural architecture. These visual comparisons serve a purpose beyond mere display: they make tangible the idea that intelligence is not a single ladder with humans at the top, but rather a landscape of different cognitive strategies shaped by different evolutionary pressures and ecological niches.
Paula frames the exhibition's mission clearly: to dismantle misconceptions about animal intelligence while demonstrating that fish can exhibit behaviors as intricate as those of humans. The research has been conducted both in controlled laboratory settings—specifically at MARE's Maritime Laboratory in Guia—and in the field, where researchers observe fish in their natural habitats. This dual approach matters. Laboratory work allows for precise measurement and controlled variables; field work reveals how those behaviors actually function in the complexity of the real world.
The exhibition is not an isolated effort. It represents an attempt to bring Portuguese scientific research closer to public understanding, to show how the study of animal behavior contributes to a fuller picture of marine biodiversity and the cognitive processes operating throughout the natural world. The initiative has drawn support from the Cascais Municipal Council, the Luso-American Foundation for Development, the "La Caixa" Foundation, and the Foundation for Science and Technology. The inaugural session on June 11th is free to attend, an explicit gesture toward accessibility.
What emerges from this exhibition is a portrait of fish not as the blank-eyed creatures of popular imagination, but as beings with inner lives—capable of learning, remembering, choosing. The research does not claim that fish think exactly as humans do. Rather, it suggests that the gap between human and fish cognition is narrower, and more interesting, than most people assume. For three months, visitors to Cascais will have the opportunity to step into that gap and see what science has discovered there.
Notable Quotes
This exhibition aims to break down misconceptions about animal intelligence while revealing that fish can possess complex behaviors, sometimes similar to those of humans.— José Ricardo Paula, coordinator and principal investigator at MARE
The Hearth Conversation Another angle on the story
Why does it matter what people think about fish intelligence? They're not going to change their behavior toward fish based on an exhibition.
You might be surprised. When people understand that fish can suffer, that they have preferences and memories, it shifts something in how they see the world. It's not just about fish—it's about recognizing that intelligence takes many forms, that it's not a hierarchy with humans at the top.
But the exhibition is in a museum in Cascais. How many people will actually see it?
That's a fair question. Three months is a decent run, and it's free on opening night. But the real work is what happens after—when someone who visited tells a friend, or when a school brings students. Science doesn't change minds all at once. It works through accumulation.
What's the most surprising thing the research has found about fish?
That they can recognize individual human faces. That they use tools. That they have personalities—some fish are bold, some are cautious. These aren't metaphors. These are documented behaviors.
And the 3D brain models—what do they actually show?
They show that fish brains, while smaller than ours, have structures that perform similar functions. The architecture is different because their world is different, but the underlying logic is recognizable. It's humbling, actually.
Do you think this changes anything about how we treat fish as a species?
Not immediately. But exhibitions like this plant seeds. They make it harder to dismiss fish as simple. And once you can't dismiss something, you have to think about your relationship to it.