Do fish feel pain? Unraveling the truth about their feelings

A quick Google search may lead you to believe that the issue of whether fishes feel pain has yet to be settled. This couldn’t be further from the truth.

There is almost universal consensus amongst scientists that fishes do feel pain, despite attempts by fish-based industries to convince unwitting consumers of the opposite. That’s why we’re taking a stand for our finned friends in an attempt to get governments to at least match the bare minimum protections afforded other farmed animals.

Note: Why 'fishes' and not 'fish'? In his book ‘What a Fish Knows’, ethologist Jonathan Balcombe points out that referring to their plural as ‘fish’ lumps them together ‘like rows of insentient corn’. But the truth is that fishes are individuals with personalities, relationships, and the capacity to feel. The Humane League UK wants to set an example of recognition and inclusion in the language we use whilefighting to improve the rights of fishes farmed for food. We advocate for using the plural ‘fishes’ instead of ‘fish’.

Do fishes feel pain?

It’s easy to imagine fishes don’t feel pain. After all, most of us rarely come into contact with them, and have been told for most of our lives that they don’t. Well, we’ve been told wrong. A mounting body of research showsthat fishes do in fact feel pain.

Do fishes feel pain when suffocating?

Resoundingly yes. Unlike us, fishes need water to breathe. Being removed from the water and pulled into a boat to suffocate is an extremely stressful and painful experience for a fish.

In fact, research has demonstrated that asphyxiation actually causes more stress than other methods of slaughter, such as using spikes or live chilling.

Do fishes feel pain when hooked?

Fishes have a number of pain receptors in their mouth, something that we’ve known since 2002. Those receptors are activated when hooked, making the experience an exceedingly painful one.

Do fishes suffer when they are dying?

Fishes do suffer when they are dying, especially when that death comes from fishing or fish farming. Many industrial fishing boats use massive nets that catch thousands of fishes at the same time, crushing those on the bottom as they are pulled from the water.

Meanwhile, on fish farms, the unsanitary and tightly packed conditions can lead to painful disease and aggression before eventual slaughter.

Do fishes feel pain in the same way as humans?

Though it’s clear that fishes do feel pain, what remains uncertain is whether or not their pain is the same as ours. Their neuroanatomy and brain activity during painful events is very similar to that of mammals, but they lack the dense folds seen in the brains of humans and apes.

Further research would be needed to understand how similar a fish’s pain is to our own, but really, isn’t the fact that they feel pain enough? Many of the experiments fishes have been subjected to in the name of establishing their pain have (unsurprisingly) involved subjecting them to significant torment, such as injecting them with acid. No being, human or animal, should have to endure such experiments.

How do fishes feel pain?

Just like other animals and humans, fishes have a delicate nervous system that allows them to feel what is happening around them.

Peripheral nervous system

Like us, a fish’s peripheral nervous system is made up of everything that allows them to feel, aside from the brain and spinal cord.

Receptors

Fishes do have receptors, or neurons, that enable them to feel what’s happening around them.

Nerve fibres

There are two types of nerve fibres in animals that together with the rest of the nervous system provide them with nociception, or the ability to feel pain. They are A-delta or C fibres. Fishes have both. However, whereas most animals have a greater number of C fibres, research has established that at least some types of fishes have more A-delta fibres.

Central nervous system

Like us, a fish’s central nervous system is made up of a brain and spinal cord. Together with the peripheral nervous system, it gathers information about what’s happening in and around the fish and passes that along to the brain. The brain in turn tells the fish how to respond to stimuli, including painful ones.

Brain

Though in some ways their brains are different from ours, fishes do still have the brain anatomy necessary to feel pain. They’ve got a pallium which, in conjunction with the rest of their nervous system, allows them to feel pain.

What is the scientific evidence that fishes feel pain?

The scientific evidence that tells us that fishes feel pain is conclusive. Studies have shown an ability to feel pain both through behavioural responses and physiology.

Opioid system and analgesic effects

In studies, scientists have injected fishes with foreign solutions and given them the option of two tanks. One of them contained painkillers but was barren, whereas the other had no painkillers but plenty of enrichment.

Though in previous trials fishes not in pain had consistently opted for the more interesting tanks, once injected, the fishes reliably chose the less interesting but pain-numbing water of the barren tank.

Protective responses

When it comes to behavioural responses to pain, fishes who have had a painful experience will rub their face and bodies against the tank walls, attempt to escape, or even stop eating.

How to identify if a fish is experiencing pain

Just like us and other animals, fishes act in certain ways when they’re experiencing pain.

Loss of appetite

Researchers have found that numerous species of fishes will eat less, or altogether stop eating when they’re in pain.

Erratic swimming

There’s no hard-and-fast rule about how a fish’s activity will change when they’re in pain. Some fishes will swim around erratically, and some will swim more often than when they’re not in pain.

Staying at the water's surface

Any avid aquarium enthusiast can tell you that when a fish is staying at the water’s surface, there is likely something wrong with the water that’s causing them to suffer. If the problem isn’t fixed, then the fish could die.

Lethargy

Though not true for all fishes, some of them will reduce the amount they’re swimming when in pain.

Rubbing their body against the aquarium walls

Experiments that subjected fishes to having foreign solutions injected into their faces found that the fish would rub the painful area against the walls of their aquarium in an apparent attempt to ease their suffering.

Is fishing cruel?

Fishes are sensitive creatures who not only feel physical pain but also form relationships with other fishes. Some even pair-bond for life, providing evidence of sentience beyond just the ability to feel pain.

Given the suffering caused by fishing on any scale, whether from a single line and hook or using massive nets, it’s clearly a cruel practice.

Why do some people believe that fishes do not feel pain?

For a long time, people were told that fishes don’t feel pain. Given how different from us fishes look, their aquatic home, and lack of vocalisation and expression, it was an easy and convenient lie to believe. However, more and more people are learning the truth.

According to Dr. Lynne Sneddon, fish pain expert, an increasing number of people are raising their hands when she gives talks and asks whether they believe fishes can feel pain. As awareness grows, it’s important that welfare policy evolves with it.

Are there opposing viewpoints?

A quick Google search of whether fishes feel pain suggests that there are competing viewpoints on the issue. However, within the academic community, the issue is considered a settled one, with almost everyone agreeing that fishes do feel pain.

There are still some holdouts, with the occasional academic article published claiming the opposite.

Comparative Anatomy

One of the most striking differences between a fish’s anatomy and that of some other animals is that fishes lack a neocortex - the complex outer layer of the brain that is responsible for our cognition and sensory perception. But the reality is that they don’t need it to feel pain. What they do have is called a pallium, and it serves much the same function as our neocortex.

Like us, fishes are vertebrates and contain many of the same structural elements that we do; a skeleton, vital organs and, most importantly in this context, a nervous system with sensory receptors.

Unfortunately for fishes, though they are built the same, they look incredibly different from us. On the whole, humans are much more likely to empathise with individuals who look, and live, like them.

Ethical implications

The ethical implications of fishes’ capacity to feel pain are pretty straightforward. Firstly, they should enjoy at least the bare minimum protections afforded to chickens and other animals used for food.

Taking it a step further, we need to ask ourselves whether it’s ethical for us to be raising them, and other animals who feel pain, by the billions, purely for slaughter and consumption.

Should we care about what fishes feel?

Caring about fishes is simply an extension of caring about your sibling, dog, or cat. It takes only empathy to see their suffering and want to prevent it as much as possible.

How you can help

One of the most effective ways you can personally stop causing fishes pain is to simply take them off your plate. Consumer demand is why so many fishes are caught from the ocean and raised on farms - without it, those industries fall apart.

You can also support our campaign to eradicate the worst suffering for fishes. Sign the petition below.