“Goldfish can feel pain”

For a long time, it was a common belief that fish, including the humble goldfish, were incapable of feeling pain. This misconception likely arose from several factors, including their seemingly simple biology, their lack of facial expressions that humans associate with discomfort, and the assumption that their brains were too primitive to process complex sensations. Some scientific arguments in the past also contributed, suggesting that because fish lack a neocortex, a brain structure prominent in mammals and linked to pain perception, they could not truly experience pain. This perspective often conveniently allowed for certain practices, such as recreational fishing, to be viewed as harmless.

However, scientific understanding has significantly advanced, challenging this long-held notion. Research has definitively shown that fish possess nociceptors, which are specialized nerve endings that detect potentially harmful stimuli like extreme temperatures, pressure, or chemicals, similar to those found in mammals. Studies have observed fish displaying a range of pain-related behaviors when exposed to noxious stimuli. These include reduced feeding, rubbing affected areas, and actively avoiding locations associated with painful experiences. Furthermore, when given analgesic drugs, fish show a reduction in these pain-related behaviors, much like humans or other vertebrates would. They also exhibit physiological changes, such as elevated cortisol levels, consistent with stress and pain.

The persistence of the myth often comes down to a human tendency to project our own experiences or, conversely, to dismiss the inner lives of creatures vastly different from ourselves. While a fish's experience of pain may not be identical to a human's, the overwhelming scientific consensus now indicates that fish have the biological mechanisms and exhibit the behavioral responses consistent with feeling pain. This understanding underscores the importance of considering fish welfare and recognizing their capacity for suffering, moving beyond outdated assumptions about their cognitive and sensory abilities.