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I+R+D

How Smart Are Fish? New Method to Study Them Discovered

Photo of author

By Milthon Lujan

Device for studying intelligence in fish. Source: Vila-Pouca et al., (2025); Methods in Ecology and Evolution, 16(5), 939-948.
Device for studying intelligence in fish. Source: Vila-Pouca et al., (2025); Methods in Ecology and Evolution, 16(5), 939-948.

For a long time, the cognitive abilities of fish have been underestimated—often studied under sterile lab conditions, far removed from the rivers, lakes, and oceans they naturally inhabit.

Traditionally, studying fish cognition has been a challenge. Researchers have been limited to observations in artificial environments, which can distort our understanding, as captivity may influence cognitive performance and behavior.

Now, scientists from Wageningen University & Research, the University of Montpellier, and The University of the West Indies have developed a simple and cost-effective method to assess fish learning abilities directly in the wild—with surprising results.

The findings, published in the scientific journal Methods in Ecology and Evolution, suggest that fish might be smarter than we thought. This article explores the innovative new device and its potential implications for aquaculture and our understanding of animal behavior.

A new tool for testing cognitive skills

Determined to overcome the limitations of captive studies, Catarina Vila-Pouca and Alexander Kotrschal, along with their team at Wageningen University & Research, developed a practical tool: a feeding board that allows fish to push disks to access a food reward—no capture or confinement required. This novel system enables researchers to study fish cognition in their natural environments, offering an unprecedented window into their minds.

How It works: evidence of autonomous learning

The device is a modular, adaptable system that can be deployed in various aquatic environments. It allows fish to interact with visual stimuli—such as colored disks covering food rewards—while researchers accurately record their responses.

“We were looking for a solution that could be used anywhere, from shallow ponds to fast-flowing rivers,” explained Catarina Vila-Pouca. “By allowing fish to make independent decisions, we gain a much clearer picture of their learning processes.” This opens the door to studying a wide range of cognitive abilities, including associative learning, visual discrimination, and spatial memory.

An innovative approach: explorers and opportunists among fish

The key to this breakthrough lies in its ability to combine the precision of lab studies with the authenticity of the wild. The device was carefully designed to minimize its impact on fish behavior, ensuring that observations reflect their true cognitive abilities under natural conditions.

The system was tested on guppies (Poecilia reticulata) in Trinidad and nine-spined sticklebacks (Pungitius pungitius) in the Netherlands. The fish showed progressive improvement in selecting the correct disks—a performance consistent with previous lab-based findings. Interestingly, the study also revealed distinct social strategies: while some individuals actively discovered the food sources (“explorers”), others took advantage of their efforts (“opportunists”).

Revealing results and their impact on aquaculture

Although the study focuses on describing the new device, its potential for aquaculture is substantial. According to Alexander Kotrschal, the method offers a valuable glimpse into fish cognition: “Studying animals in their natural habitats allows us to better observe their authentic behavior. This not only enhances our understanding of cognitive evolution, but also has important implications for conservation and animal welfare.”

Better understanding fish cognition could lead to:

  • Improved animal welfare: Deg more stimulating and enriching farming environments that promote natural behavior and reduce stress.
  • Optimized feeding: Understanding how fish learn to find food can help develop more efficient and sustainable feeding strategies.
  • Genetic advancements: Identifying desirable cognitive traits could selective breeding programs.
  • Enhanced conservation efforts: Applying this knowledge to protect species in their ecosystems.

Conclusions: A versatile and accessible device

This new, low-cost device—easily adaptable to different fish species—is well-suited for studying social learning and memory. It represents a milestone in fish cognition research. By allowing us to observe the intelligence of these animals in their own world, it opens up a range of possibilities for both scientific inquiry and practical application in aquaculture.

The researchers hope that this simple innovation will significantly advance the field of fish cognition research. In the future, we may see notable improvements in farmed fish welfare, production efficiency, and our broader understanding of animal behavior.

The study was funded by ASAB, KNAW, the Lucie Burgers Foundation for Comparative Behaviour Research, and the Dr. J. L. Dobberke Foundation for Comparative Psychology.


Catarina Vila-Pouca
CEFE, Univ Montpellier, CNRS, EPHE, IRD
Montpellier,

Behavioural Ecology Department, Wageningen University and Research, Wageningen
The Netherlands
Email: [email protected]

Alexander Kotrschal
Behavioural Ecology Department, Wageningen University and Research
Wageningen, The Netherlands

Reference (open access)
Vila-Pouca, C., Waele, H. D., Parsékian, A., Erroi, S., Rooij, M. D., Labohm, E., Deacon, A., & Kotrschal, A. (2025). A novel apparatus for studying fish cognition in the wild. Methods in Ecology and Evolution, 16(5), 939-948. https://doi.org/10.1111/2041-210X.70002