There is ever-emerging evidence that fish, like other animals, are intelligent, complex, sentient beings capable of experiencing pain and suffering like the dogs and cats we share our homes with. Fish are notoriously difficult for humans to empathise with; they look so different to us and their responses to pain are unlike ours and other land-based animals. This has unfortunately led to the commonly held belief that fish just do not feel pain at all, which could not be further from the truth.

This image has an empty alt attribute; its file name is l-11fFfVpO_o87hkBzLbEJIyyPYir5OFyAsMlCxJmHCL33hkCQPVjUUoqddGPsQ3QmS5bzl5WOeWb5D_ml4bJgPNtV26S39xUu-kWGpX-rC6O5ZjTMmXQ3F5VoEYLrq18Lk3d2mb

Can fish experience pain?

The indicators of pain we commonly look for in humans and other land-based animals are largely absent in fish and other marine animals (they don’t vocalise the way other animals do, they move their bodies in differing ways to escape pain) and this has consequently led many to believe this is simply because fish are incapable of experiencing pain. 

Several experiments have been done to establish whether or not fish and other marine animals are able to feel pain and suffer in ways similar to us and other animals.

This image has an empty alt attribute; its file name is DvkE3vlPE1HzORE12WQN8x5TIsM3LtkBR_WTrG4Fu79IpCmXsb7DZM4CJRqBuXg7m3rqdgSbBkShcNyotJI2qxkfifeuqUMBy5MLuZw8E5CZLCRTTbPo1ktyYbWD5dFAXwHbOeba

NOTE: Kindness Project does not condone the use of animals for experimentation, however these experiments have been important in shaping attitudes within the scientific community regarding fish, their sentience and ability to feel pain and suffer.

One study saw a group of rainbow trout given acidic injections into their lips while another control group had their lips injected with saline.

Fish who were given acidic injections were observed breathing rapidly, rocking back and forth at the bottom of their tank, rubbing their lips on pebbles and the sides of the tank and took twice as long as the other control group to commence eating again following the injections.

This image has an empty alt attribute; its file name is MeL6EiuLB_M_iqtLXWLsWLp8TjbxOtB9BmMF81Ikwr9HF9v1uUfIIU0VhHALygYroCq6vRiQ-8uytw-WNXcnWB5u9S_pAFC7MutlCF49UmyMXEfzUXeSZGY2qJWUYO3fbnBUFYZE

In another experiment, to dull their pain of the injections, some fish were given morphine. Morphine works to lessen the experience of pain, however it does not cure the source of pain. When fish are exposed to coloured blocks in experimental environments, they normally react defensively. When injected with acid, they exhibit these defensive behaviours much less, likely because they are distracted by the painful stimuli. However, when injected with morphine plus the acid, their behaviours return to normal (ie. they react defensively once again). This implies that fish are reacting based on their mental state during pain, not just as a mechanical response to a painful stimulus – in other words, this implies fish have a conscious experience of pain. 

Preferences and avoiding pain 

In an experiment conducted by Lynne Sneddon, biologist and expert in marine biology, fish were given the choice between two tanks to live in. One tank was dull and empty, the other had enrichment like plant matter, pebbles and view of other fish. Consistently, fish chose the tank with enrichment over the empty tank. However, when fish were injected with a painful acid, and only the barren tank contained pain-relieving lignocaine, fish consistently chose the barren tank. This was repeated, only this time with the pain relief injected directly into the fish, and subsequently they returned to choosing their preferred enriched environment.

This image has an empty alt attribute; its file name is sWWamj7R2bZUhkNaFovtfZrhcqQsube8TxJ8RJVu3ytceDABhQ8RDPPnbeHmIHkSMTlBpHOv2mjRT3V4iDqcSHRgsWVY-Z8cEF7akuzIic35X1jeOLI-d428Dcowua_zEslwjo17

Remembering pain

Not only are fish capable of experiencing pain, but they even possess the cognitive abilities to remember pain and act to avoid it. Fish can swiftly learn to steer clear of negative stimuli and will continue to do so for extended periods. Take for example the pike fish, who commonly experience ‘hook-shyness’ following being painfully caught on a fisherman’s hook, will assiduously avoid them for over a year after the experience. Similarly, rainbow fish are capable of learning escape routes from nets and remember them for at least a year after. 

Farmed fish 

According to the United Nations, a staggering 52% of fish products produced in 2018 were accounted for by factory-farmed fish.

Research has revealed that up to a quarter of farmed fish express behaviors and brain activity comparable to that of extremely stressed and depressed humans. These fish often show a pattern of stunted growth, which could be indicative of their emotional state in fish farms.


This image has an empty alt attribute; its file name is WZDxlsjaNvvXtWriKvb_LOxGHFxJtvlATuRs_jMJOYrK2lqIk2XPuFhLpoyj9IGlDj3yDyxyFzusCtbJtYJ95_U9tnOVLaelbxpa_G3_Cud0LnMXws8j0HIKltxM1Bjb6Z-PHerJ
Salmon having her egg squeezed out (‘milked’).

Broodfish (fish used for breeding) have their eggs and milt (sperm) collected in a hatchery. Female fish are cut open and have their eggs scooped out from inside of them in a process commonly referred to as ‘milking’. Male fish have their sperm squeezed out from inside of them to combine with the females’ eggs. The eggs are then incubated until the baby fish (fry) are independently feeding, at which point they are moved to rearing tanks.

This image has an empty alt attribute; its file name is zdGq2bsrmpxGW5SMeWUxcITcGgX_WXSXvGUQqAZThyt8j4Y08UY-E_6J9qOo_mZOHWl5O3VoStGnY2m7BqKLkSSMyQvpaduZIa36ms_ittsk2Rnb_YgUmDAEXZNniwJ3JbcuwE1r
Male fish having milt squeezed from them to combine with the females’ eggs.


Farmed fish are bred indoors in hatcheries. When fish grow they are moved to numerous tanks at the facility. Take for example salmon, who live up to 16 months of their lives in on-land tanks.

Depending upon whether or not fish are a freshwater or saltwater breed the way they are raised differs.

Aerial view of a fish farm.

Cages and tanks

Freshwater breeds of fish, like the murray cod, spend their whole lives – years – in either outdoor pens or indoor tanks.

On land fish farming tanks. Image: aquaculturemag

After the hatchery stage, some breeds of saltwater fish, like salmon, are forced through pipes into tanks that take them out to underwater cages in the ocean where they will live for up to 18 months before they are killed. Salmon are crammed into these underwater cages with thousands of other fish, deprived of the ability to live their lives as they would in nature.
There are many species of fish that swim thousands of kilometers throughout their life, and yet in supposedly ‘high welfare’ Tasmanian fish farms the maximum circumference of the underwater cages is a pitiful 240 metres.

Sea cages holding thousands of farmed fish. Image: The Conversation

The health of factory-farmed fish is impacted greatly by the way they are raised. The close confinement with thousands of other fish means diseases can spread quickly. A common disorder in farmed fish is amoebic gill, which is caused by a parasite that thrives in warm waters; particularly concerning given this is likely to increase with climate change. The disorder is characterised by difficulty breathing and deteriorated gills, and can have high mortality rates when left untreated. 

Unsurprisingly these diseases can spread to wild populations too, causing even more suffering and contributing to the concerning reality that we may face fishless oceans by 2050. 

Sick salmon in a sea cage. Image: BBC

Health issues of farmed fish are, in some cases, treated using ‘sea baths’. This involves forcing fish through tubes into freshwater tanks, before pushing them back out to the underwater cages. In the summer months, these baths occur frequently, causing huge amounts of stress to the fish subjected to this process. It is also a dangerous procedure, and thousands of fish have died during the process due to ‘human error’.

This image has an empty alt attribute; its file name is Km395Z9RlDSbvpK75K4oUKmGe-RgSrvA8UxzYwJexMhs0djZ21V7SA_tKx0OWT0EEwSooVZMnVVvAXPVCIFdk1a-fVtaW3e4jO382IAQtJnMtVAxxJDeIbhLwjgrq265QcuU5lZ5


Most commonly, fish are killed by asphyxiation, which is a long, agonising suffocation. An ‘icy slurry’ is sometimes used in this process, however, fish still take several minutes to die. 

This image has an empty alt attribute; its file name is 34Zby9zVZChYBkDjdl1GjzHa_de5WTLQTtxC5uD-9M1xG5rAr2M6QmOmb-gx1SeksqKcfotC6uwHxScUCEIjwh4_Hj8lvuKxdwkOCqXS6b3TwRHUP3B7_6aLwj8mnWYfvRaanWZ3

Some supposed ‘high welfare’ farms use stunning methods to render fish unconscious by:

  • ‘Percussive stunning’ – a form of blunt force trauma where the skull of the fish is smashed with a heavy blow that hits the brain.
  • ‘Electrical stunning’ – where fish are submerged in live water.

After this, fish are bled out and gutted.

Wild-caught fish

It is estimated a massive one trillion fish are caught and killed each year. 

Not included in this figure are fish caught illegally, non-target species (by-catch), and other undocumented forms of fishing.

If the rate of fishing and other oceanic destruction continues the way it is currently, we are facing the very frightening reality of fishless oceans by the year 2050.

Being caught on hooks and in large nets is, unsurprisingly, extremely traumatic for fish, who have been found to warn one another of oncoming danger.

This image has an empty alt attribute; its file name is lr5NfNu-_qg_bjnZQH-3y4Sz7X7NR7cavmt8kbhkBOxwf5CzQuqZ6NjDsNq2YwVITjbkDdnBH52MHwMQv9VEo1ZwVoSkAXF7KhqBxj_JEgO1uK5evTqUuuTgJF0r6g9i7L__cRNr

Net fishing 

Net fishing sees fish being forced together tightly in close confinement. Out of the water, fish are unable to breathe and often unable to see around themselves when piled among thousands of other fish. Most commonly these fish die slowly and painfully by asphyxiation. It is estimated that around 80% of fish caught are done so in nets. 

There are a variety of nets used:

Purse Seine Nets

The most practised method of fishing is distinguished by a fishing vessel finding a school of fish, and, using a crane, surrounding fish with a net. The ends of the net are pulled together, much like a drawstring bag, and are pulled aboard with the fish inside.

The netting is commonly used to catch salmon and tuna. These nets can stretch as much as 2 kilometres in length and be 200 metres deep. These nets can catch a huge 1,500 tonnes of fish at one time. Just one net has the capacity to capture up to 43,400 skipjack tuna or 8,500 fully grown yellowfin tuna for slaughter.

FADs, which are floating devices used to attract fish, are used in 65% of seine net tuna fishing. FADs are said to attract more unintended animals like sharks and juvenile fish. 

Trawling nets 

This image has an empty alt attribute; its file name is bbYU_YPvMcIzlstGIkZWYxHjd4iYmdAejLuPKnOInXfzddMPEYQK9HSgJHnn1qFDWj6zpKppr8jW-Ggcd52UuXHm9WDuATNxOuPoviQJ7VuNu_vqxMNvIaPKs3dhMf9nwMuppB1U
Trawling fishing involves a fishing vessel towing a net for long distances until it is filled with fish. A super trawler. Image: Pierr Gleizes / Greenpeace

Trawling fishing involves a fishing vessel towing a net for long distances until it is filled with fish.

This video gives us a sense of the sheer scale of trawling nets. Fish are forced aboard the fishing vessel and emptied into a void space on the fishing vessel, often hitting the bars and walls on their way down. In this video you can see fish as they struggle to breathe.

Bottom trawling

Bottom trawling entails dragging weighted nets across the sea floor, capturing animals in it’s path. Bottom trawling is commonly used to catch prawns, squid and flat head, as well as other sea animals. This method of fishing is also, arguably, the most destructive to the environment.

Bottom trawler. Image: Greenpeace International

Squid are a breed of cephalopod, alongside octopus and cuttlefish, recognised as highly complex and intelligent animals.

Gill nets

Gill nets are invisible to fish, and can reach across several kilometres. When fish swim into the nets they become trapped, and when they attempt to escape they become caught by their fins, spines and gills. This is, unsurprisingly, extremely stressful for fish, who often suffer further injury as they thrash around in a desperate attempt to escape.

Diagram of a gill net.

Gill and trammel (a similar type of) nets are the most widely used fishing gear around the world, and are used to capture gummy shark (‘flake’ fish) in Australia.

These nets are non-discriminate and as a result often catch non-targeted marine species such as sharks, known as by-catch.

Shark caught in gill net.


Longlines are utilised to catch a variety of species of fish dependent upon where and at what depth they are placed. Blue cod, swordfish, tuna and gummy shark are some of the species targeted by this fishing method, among many others.

Infographic on longlines. Image: Greenpeace

Longlines can be up to 150kms long with up to 3,000 hooks attached to it. They are left in the water for long periods of time – hours – before being pulled back aboard the fishing vessel. This means any animals that become caught on the hooks suffer for hours trying desperately to escape.


Gaffing is when a large hook is used to drag fish aboard a boat from a longline. The fish are essentially stabbed while they are fully conscious.

Environmental impact of fishing

A shark caught in the fishing process. Image: …

Environmental impact of farmed fish

There are a number of environmental implications that arise due to aquaculture, which differ depending on what species of animal is being farmed. 


A majority of farmed fish are carnivorous and rely upon wild-caught populations of fish for feed. This means that fish must be caught from the wild in order to feed farmed fish populations. Over 50% of the world’s fish oil is used in feed for farmed salmon. According to FAO, a massive 77% of the world’s fisheries are either over-exploited or fully exploited. This means fish populations are being caught at a rate faster than they are able to replenish themselves. Overfishing is one of the biggest threats our oceans face, threatening ocean ecosystems. 

Thousands of fish caught in a net. Image: Unsplash

Further, nearly all methods of fishing are non-discriminate and contribute to something known as by-catch. By-catch refers to the non-targeted species of marine animals that are killed by commercial fisheries each year. The worst affected marine animals are those that are otherwise long-living and slow-breeding. Whales, dolphins, turtles and albatrosses are some of the worst affected species. It is estimated that 20 million of these individuals are killed by the fishing industry each year as by-catch. 

Waste/ antibiotics and pesticides.

Fish farms produce a considerable amount of waste that impacts the surrounding environment and ecosystem. The waste produced by fish farms spills out into the wider ocean, causing nitrogen pollution. This can lead to the depletion of oxygen in the water, which can consequently severely stress or kill wild populations of fish. Further, a huge amount of antibiotics and pesticides are used in fish farming in an attempt to reduce the prevalence of disease, which can also impact upon wild populations of marine animals. 

Not only are the surrounding areas of fish farms impacted by effluent, wider coastal zones can be affected at different ecosystem levels, consequently reducing biomass, density and diversity of the nekton, plankton and benthos, and altering natural food webs.

Genetic disruption 

Fish that are farmed in underwater sea cages can sometimes escape, posing a risk of them breeding with wild populations. Salmon, for example, escape from fish farms in the thousands each year. This may seem harmless, however, this can significantly damage wild populations of fish by introducing negative genetic traits and consequently eroding wild gene pools.

Environmental impacts of wild-caught fishing.


Fish on the deck of a fishing vessel. Image: Selene Magnolia 

As much as 90% of the world’s fisheries are over-exploited or fully-exploited, meaning fish populations are unable to replenish themselves at the rate in which they are being fished. Some fish populations have been fished to the brink of extinction. Scientists have estimated if we continue to fish at the rate we are currently, we may be facing fishless oceans as soon as 2050

Overfishing not only affects the populations of targeted species, but can have an adverse effect on marine biodiversity, impacting entire ecosystems. When too many fish are removed from our oceans, imbalances occur that have the potential to erode the food web, which leads to the loss of other marine life. 

Habitat destruction 

Bottom trawling destruction. Image: Mar Mas / OCEANA

As well as removing fish that are important to the ecosystem and food-web of the ocean, many industrial fishing practises are extremely damaging to the environment. Take bottom trawling as an example; the weighted equipment is dragged along the seafloor, often destroying corals, sponges and oysters, which create productive marine habitats. The impacts of this can be far reaching. For example, oyster reefs have been destroyed in many places because of bottom trawling. Oyster reefs play an important role as filter feeders, helping to remove excess nitrogen from the water. Without these reefs bodies of water can succumb to eutrophication, caused by excess nutrients in the water, and consequently killing many more marine life.


Image: WWF

By-catch refers to the non-targeted species caught by commercial fishing vessels. These species include whales, dolphins, sharks, sea turtles and sea birds like albatross. Take for example longline fishing, which is one method responsible for huge amounts of by-catch. Longlines can stretch for over 100km and have thousands of hooks attached to them; any animal that takes the bait becomes caught on these lines. Sea turtles commonly drown caught on longlines as they cannot reach the surface to breathe. Albatross often dive to retrieve the baits and become stuck and die on the longline too.

Littering the oceans

A turtle entangled in ghost fishing gear. Image: Blue Ocean

Fishing gear that has been lost or forgotten poses a huge threat to marine animals, as they continue to catch animals; this is sometimes referred to as ‘ghost fishing’. A huge range of marine animals become entangled in lost or discarded fishing nets, including whales, dolphins, turtles and sharks.

Human Impact

Human rights violations aboard fishing vessels

The fishing industry is rife with human rights abuses; far out of sight and mind of law enforcement, workers are extremely vulnerable at sea. A number of reports have brought to light the continued use of forced labour, physical punishment and deliberate killing of workers in some sectors of the fishing industry. Consumers buying seafood products may be unwillingly funding a continued cycle of human exploitation and abuse at sea.

Image: Daniel Murphy for Human Rights Watch.
Image: Daniel Murphy for Human Rights Watch.

Another report spanning across 13 countries, including the US and some from the EU, highlighted issues of debt bondage, inadequate food and water aboard vessels, filthy living conditions and physical and sexual assault.

Due to globalisation, companies are able to rely on tangled international supply chains, which allow cheaper labour. This means many of these human rights violations are happening to people from developing countries, to meet demands of people in western, developed countries.

Mental health of workers 

Aboard fishing vessels workers are continuously exposed to violence and death inflicted upon fish and other marine animals. When a person carries out repeated acts of violence on animals, they become vulnerable to developing a type of post traumatic stress disorder known as Perpetrator-Induced Traumatic Stress disorder, or PITS. Sufferers can experience symptoms of depression, panic, paranoia, and dissociation.

To read more about the human related impacts of the animal industrial complex click here.

Jurnasyanto Sukarno / Greenpeace


Gardein fishless filets

These are the perfect alternative to fried fish from the fish and chip store. Team them with Masterfoods’ tartare sauce (yes, it’s vegan!) and some oven or air fried chips and you are all set.

Gardein is a totally plant-based company so you can enjoy their entire range without supporting animal exploitation and cruelty. Available in Australia, Canada, UK, USA

Also try: 

  • Fry’s family: fish-style fillets. (Entirely vegan company) Available in South Africa, United Kingdom, United States and Australia.
  • Quorn: breaded fishless fillets (clearly marked vegan items) – available in Australia, Belgie, Belgique, Danmark, Ireland, Nederland, New Zealand, Norge, Philippines, Schweiz, Suisse, Singapore, Suomi, Sverige, UK and USA


This may seem surprising but chickpeas are an amazing alternative to tuna. Mash the chickpeas with a fork, add some lemon juice, diced red onion, vegan mayonnaise, diced celery, salt, pepper, garlic powder and any other herbs, spices or vegetables that you might like to add and there you have it. A perfect alternative to tuna that you can enjoy in sandwiches, on crackers in salads or straight from the bowl.