Why fish are excluded from a vegan diet is a common source of confusion for many people exploring plant-based eating. Fish and other aquatic life are often mistakenly categorized as separate from “meat,” leading to the assumption they might be acceptable in a diet focused on animal welfare. The reasons for their exclusion are multiple, stemming from the foundational philosophy of the lifestyle, the scientific understanding of aquatic animal suffering, and significant environmental concerns.
Defining Veganism: The Core Principle
Veganism is a philosophy and way of living that seeks to exclude, as far as possible and practicable, all forms of exploitation of, and cruelty to, animals for food, clothing, or any other purpose. This definition extends beyond simply avoiding the flesh of land animals like cows or chickens. The fundamental rule is the exclusion of all products derived from animals, and fish are biologically classified as animals.
Adopting this lifestyle means abstaining from consuming any organism within the kingdom Animalia, including fish, shellfish, and other marine life. This is the primary answer to why fish are not eaten by vegans. The core principle is an ethical stance against the commodification and use of any animal, regardless of whether that animal lives on land or in the water.
This philosophical basis treats a fish as an individual with an inherent right to life. The consumption of any animal product, including fish, immediately disqualifies a diet from being considered vegan. The exclusion is based on the moral rejection of animal exploitation, not a biological distinction between aquatic and terrestrial life.
The Ethical Argument: Fish Sentience and Suffering
Beyond the definition of fish as animals, the ethical argument for their exclusion is supported by the scientific understanding of their capacity to feel pain. Research provides compelling evidence that fish are sentient beings, capable of experiencing suffering and emotional states. They possess nociceptors, specialized sensory receptors that detect harmful stimuli, and exhibit physiological and behavioral responses to painful events.
Studies have identified Substance P, a neurotransmitter associated with pain transmission in mammals, in the central nervous system of fish, suggesting a similar pain pathway. Behavioral experiments show that fish actively avoid painful stimuli or seek out environments where painkillers are present. This demonstrates a conscious response to distress, indicating their experience of pain involves more than a basic reflex.
The methods used to catch and kill fish in commercial fishing present ethical concerns regarding suffering. When fish are hauled out of the water, they often undergo a prolonged death from suffocation. For deep-sea fish, rapid pressure change during retrieval can cause barotrauma, damaging internal organs and causing eyes to bulge. These methods inflict distress, contradicting the vegan commitment to minimizing harm.
Environmental and Sustainability Concerns
The decision to exclude fish is influenced by the ecological impact of the fishing industry on ocean health and biodiversity. Overfishing represents a global crisis, with an estimated 90% of the world’s fish populations classified as fully-fished or overfished. This depletion disrupts the marine food web, destabilizing entire ecosystems.
Many common fishing techniques cause widespread habitat destruction, particularly bottom trawling, which involves dragging heavy nets across the seafloor. This practice has been likened to marine deforestation, destroying fragile habitats like deep-sea coral and sponge ecosystems that can take decades to recover. Damage to the seabed also releases carbon stored in marine sediments, exacerbating the climate crisis.
A further concern is bycatch, the unintended capture and death of non-target marine life. Industrial fishing gear, such as trawl nets and longlines, are unselective, resulting in the incidental capture of thousands of tons of other animals, including dolphins, turtles, and seabirds. Bycatch can represent up to a quarter of the total marine life caught, and the discarded animals are often thrown back into the ocean dead or dying.
Clarifying Related Diets
The confusion about fish and veganism often arises from blurring the lines between various plant-focused diets. Veganism is distinct from vegetarianism, which excludes the flesh of all animals, including fish, but typically permits animal-derived products such as dairy and eggs. A vegetarian diet is characterized by the absence of meat and fish, but not necessarily all products of animal exploitation.
Pescetarianism is a distinct dietary pattern that excludes land-based meat and poultry but includes fish and other seafood. Individuals follow this diet often for health benefits, such as obtaining Omega-3 fatty acids, or for environmental reasons related to avoiding the high impact of terrestrial animal farming. However, because a pescetarian diet involves consuming animals, it is incompatible with the ethical standards of veganism.
The inclusion of fish or any other aquatic animal product means a diet cannot be classified as vegan. For vegans, the exclusion of fish is a direct consequence of the core belief that all animals should be free from human exploitation.