Do fish have emotions? What science reveals about fish feelings

As you sit and watch a goldfish swim in its bowl or a school of fish glide effortlessly through the open sea, you can’t help but imagine what they’d be like as uncomplicated, instinct-driven creatures. Yet, for several decades, scientific research has consistently pushed us in a different direction, one that’s more complex than you’d think.

Scientists have been able to uncover evidence that indicates just how complex fish actually are, getting well beyond what most people consider typical ‘fish behaviour.’ They don’t just act on instincts; they learn, remember, socialise, and even react to their experiences in such a way as to suggest emotions and feelings. This manifests in a changing paradigm that’s giving way to a whole new perspective on fish behaviour and well-being.

Do fish have feelings: What the evidence says

For many years, it was believed that fish could neither feel pain nor sensations the way we do because of the enormous difference in the structure of our and fish brains. However, a study named “The evidence for pain in fish: the use of morphine as an analgesic” published on Science Direct proves that fish possess unique nerve receptors, called nociceptors, which indicate noxious or pain-causing stimuli. Upon such stimulation, fish, in addition to twitching, will alter their behaviour and slow down, rub the affected area, or avoid a particular spot. Such a change indicates a true reaction to pain, and not a mere reflex.

Nonetheless, it is not all bad. Fish, like any animal, are capable of feeling positive experiences—pleasure, social interaction, and even joy. They live in close social groups, engage in complicated behaviours, and perform complex courtship displays when looking for females, indicating a depth of emotion.

Behavioural signs of emotion in fish

Fish do not wear their emotions on their faces or through their speech the same way mammals do. They are interpreted through their behaviour. So, keeping an eye on their behaviour to know how they feel is highly necessary.

• Response to pain

Pain response is apparent by changes in feeding, altered swimming patterns, and rubbing of affected areas.

• Social bonds

Social ties are evident through fish recognising and preferring the association of their known neighbours.

• Learning and Memory

Learning and memory can be observed in goldfish that remember incidents for a period of three months, distinguish between shapes and colours, and can also detect time cues.

• Cooperation

It is manifested when different species come together to hunt or to avoid danger.



Collectively, these trends are more complex than simple instinct and indicate a sophisticated emotional and intellectual capacity among various fish.

Pain and stress: More than just reflexes

There has been a longstanding notion that fish respond to pain in a mere reflex fashion, for example, retracting from the source causing the pain. However, a study titled “Brain serotonergic activation in growth-stunted farmed salmon: adaption versus pathology” published in Royal Society Open Science, suggests a greater complexity in response, including behavioural and physiological alterations, such as increased stress hormones and changing behaviour, that do not relate to pain responses in a purely reflex manner. That pain-relieving drugs can reduce these responses in fish further supports their ability to experience pain.

Why understanding fish emotions matters

The implications of our new understanding of fish emotions have immense repercussions. Every year, billions of fish get caught or reared in tanks. With billions of fish caught, farmed, or kept in captivity every year, recognising that fish can feel and experience emotional states challenges how we approach fishing, aquaculture, and pet care. If fish have emotions and can feel pain, it becomes an even more daunting task to discuss their welfare.