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Good animal welfare depends on three components:

  • Physical well-being
  • Mental well-being
  • Natural living.

In intensive fish farms, all three of these are compromised by overcrowding in poor conditions, starvation, and inhumane slaughter methods, such as suffocation.

Welfare issues for farmed fish


In fish farms, large numbers of fish are confined in a small area which can cause serious welfare problems. Salmon, while around 30 inches long, can be given the space equivalent of just a bathtub of water each. 

Silver Pacific Salmon swimming underwater

Overcrowded fish are more susceptible to disease and suffer more stress, aggression, and physical injuries such as fin damage. Along with lack of space, overcrowding can also lead to poor water quality, so the fish have less oxygen to breathe.

Natural behavior

The behavioral requirements of most of the fish species used in aquaculture are poorly understood. It is unlikely that the conditions in intensive farming meet even the basic needs of fish.

For example, rearing fish in cages prevents their natural swimming behaviour. Salmon are migratory, and would naturally swim great distances at sea. Instead, they swim in circles around the cage, rubbing against the mesh and each other.


Food is often withheld from farmed fish before a stressful procedure, such as transport or grading (sorting into groups of similar size), and slaughter. No more than two or three days are normally needed to empty the gut, but some fish may be starved for two weeks or more.

Death by suffocation

Farmed fish are slaughtered by a range of methods. Some methods cause immense suffering, such as gassing with carbon dioxide or cutting the gills without stunning. Some fish are simply left to suffocate in air or on ice, or may be processed while still alive. Other methods are more humane, such as electrical stunning or a strike to the head. 

There are alternatives to intensive farming of fish with much higher welfare potential.

Higher welfare alternatives for fish

Higher welfare farmed fish

Fish can be farmed more humanely than conventional intensive farming. Organic standards, such as those set by the Soil Association, improve the welfare of farmed fish.

Contrary to organic standards for other animals, fish may still be confined in cages. However organic farmed fish benefit from more space and are slaughtered using more humane methods. In addition, Soil Association organic standards limit starvation periods and only allow wild fish to be used as feed for farmed fish if they were sustainably caught.

Wild-caught fish

fish caught in orange net

Wild-caught fish do not experience the welfare problems of being reared in cages, but are still largely slaughtered by inhumane methods - see

The sustainability of wild fish stocks is also under serious threat. Wild fish from sustainable stocks are available - for more information visit


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