Fish Who are Farmed


Aquaculture, the farming of aquatic animals, is growing rapidly. It is one of the fastest growing sectors of animal-based food products. By 2018, it is expected that humans will eat more farmed fish than wild-caught fish. By 2022, aquaculture output is expected to rise by 33%.

Fish are subjected to painful slaughter, filthy and crowded living conditions, and abuse like many farmed land animals.

how are fish raised in farms?

On farms, fish are kept in artificial ponds or cages in the open water. Many fish are crowded into a pond or cage, so they fight and injure one another. The overcrowded conditions make the water filthy and cause outbreaks of disease. Like farmed land animals, fish are fed antibiotics and growth hormones. Fish also have their bodies mutilated without painkillers. Farmers often tag fish by cutting off part of their fins. Other factors that may affect the welfare of farmed fish include the feeding schedule, stocking density, water quality, and water temperature.

Farmed fish also suffer from deformities, outbreaks of parasites, and depression. Many fish are physically deformed because they are forced to grow so quickly. Half of farmed salmon are at least partially deaf due to inner ear deformities. Sea lice are common on fish farms, and can spread to wild fish in open water systems. They feed on the mucous, blood, and tissue of fish, and can even eat the tissue down to the bone. When the damage to a fish’s head is severe, their skulls can be exposed (a condition known as the “death crown.”) Some fish, called “drop outs,” suffer from depression so debilitating that they float lifelessly at the water’s surface.

Before fish are transported to slaughter, they are starved, anywhere from a few days to a month. Fish are transported to slaughter in boats. They endure stress and injuries from being crowded together in nets and removed from the water. The transport time can be up to thirty hours. Entire shipments of fish transported in boats have died.


Fish are slaughtered in brutal and painful ways. Most fish are killed when they are fully conscious and can feel pain. US law does not require that fish are unconscious, and therefore cannot feel pain, before they are killed. (The law also does not require this for chickens, who together with fish, make up the majority of animals killed for food in the US.)

In a commercial fish slaughterhouse, fish are usually placed in chilled or ice water, or water with high levels of dissolved carbon dioxide. This causes the fish to stop moving, but does not render them unconscious. When the fish stop moving, they are taken out of the water, sliced open, and bled out. Most fish are fully conscious when killed. When fish are put into ice water, they violently try to escape. It takes about three to ten minutes for fish lose consciousness after being placed in ice water. Fish are also routinely suffocated by taking them out of the water; or fish are taken out of water, sliced open, and allowed to bleed and suffocate to death.

carp heads after slaughter in Mlynec village, CZ, CC Breta Valek

Fish who are taken out of water and gutted alive suffer for about five minutes to more than an hour before losing consciousness. Fish who are only taken out of water, but not gutted, suffer from almost three minutes to more than four hours before losing consciousness.

Similar to the slaughter of land animals, egregious animal abuse has been shown at fish slaughter facilities–an undercover investigation by Mercy for Animals showed employees slicing off fins, tearing the heads off, and peeling away the skin of fish who were alive and conscious.


Pain and Fear in Fish by Paul Ashley & Lynne Sneddon in Fish Welfare (2008).

Fish Farmer’s Perspective of Welfare by Nick Read in Fish Welfare (2008).

Welfare of Fish at Harvest by David H. F. Robb in Fish Welfare (2008).

Worse Things Happen at Sea: The Welfare of Wild-Caught Fish by Alison Mood,, (2010).

Deafness in farmed salmon linked to accelerated growth by ScienceDaily (2017).

Lice-Hunting Underwater Drone Protects Salmon With Lasers by Michael Dumiak (2017).

Brain serotonergic activation in growth-stunted farmed salmon: adaption versus pathology by Vindas et al., Royal Society Open Science (2016).