Do Fish Feel? Studies on Fish Capabilities Suggest Sentience

Posted by Samantha Bubar

We've all heard the myth that fish have a three-second memory.

That may not be the case. Have you ever wondered if your fish has feelings?

Recent, and ongoing, research sheds light on a new perspective. An article titled "Fish Can Show Emotional Fever: Stress-Induced Hyperthermia in Zebrafish" by Sonia Rey, Felicity A. Huntingford, Sebastian Boltaña, Reynaldo Vargas, Toby G. Knowles, and Simon Mackenzie explore the "unresolved and controversial" schools of thought around what, and how, fish may feel.

They come to some pretty convoluted conclusions, and prove that fish are, in fact, sentient beings.

A primary response to the question of fish feeling is essentially that the brain of a fish is too small and therefore very simple.


The authors of the zebra fish study note that "...fishes have little capacity for learning and memory and a very simple behavioral repertoire," and that because of the size of their brain, fish "lack the cognitive ability to experience suffering and their responses to adverse circumstances, while perhaps  more than straightforward reflexes, are still very simple and have little or no emotional content."

This suggests that because the fish brain is so small, it functions on a primarily instinctual basis; that fish are not responding with an emotional backing, but simply driven by instinct to do what fish do.

Others believe that fish are very capable of having feelings.

According to research and studies that have been done, the brain of a fish has parts that are responsible for emotion, learning, and spatial memory, which suggests that fish indeed have feelings.


Studies have shown that fish have the capability to notice harmful stimuli and react to that unpleasant stimuli though physiological changes, movement, change in motivation, and change in attention. There has to be a certain level of consciousness and emotion to be able to perform those actions.

Behaviorally, both in the wild and captivity, fish have shown to be capable of quite a bit more than we give them credit for. The New York Times article Fishes Have Feelings, Too highlights a great number of these examples and further suggests that fish are sentient.

An initial study of manta rays in the Bahamas who reacted to a mirror placed in their enclosure provides the conclusion that they have a sense of self. They didn't try to interact with the reflections in the mirrors, as if they were other rays, but rather "showed off," blowing bubbles and watching themselves. They seemed to make the distinction that the reflections were not separate manta rays, but actually reflections of themselves.

The only other animals that show this type of awareness are humans, great apes, dolphins, elephants, and magpies.


Another fish that exhibits incredible intelligence is the frillfin goby. This fish memorizes the pattern of tide pools, and is able to jump to another tide pool with complete accuracy if a danger is present. They map the reefs' topography when the tide is high and then are able to remember the pools when the tide is low. It takes incredible neurological connections to remember spatial topography like the frillfin goby does.


There are also many studies of fish that hunt together with eels to maximize likelihood of a meal, fish that clean other fish (and react to the accuracy of the job the cleaner fish is doing, sometimes moving elsewhere if the cleaner fish isn't doing a great job), and fish that seek out touch when stressed.

So are fish sentient beings? The jury is still out. But the complex relationship that fish have between the consciousness of their surroundings and different levels of emotions makes a pretty strong case that fish can feel. As the authors of "Fish can show emotional fever: stress-induced hyperthermia in zebrafish" concluded, this connection has:

"...important implications both for how the welfare of fishes is conceptualized and protected and for our understanding of the evolution of emotions and consciousness in vertebrates."

Whether you believe fish to be simple minded or rather complex, science is continually shedding new light on what species are capable of, and what they are feeling.

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Do Fish Feel? Studies on Fish Capabilities Suggest Sentience