Do fish feel pain?
Yes. Fish, have pain receptors, behave erratically when harmed, remember what injures them, and respond to pain killers. Pain receptors
Fish pain receptors similar to other animals
Fish have nerve receptors, similar to those found in amphibians, birds, and mammals, which detect painful events. In one experiment, twenty-three pain receptors were found on the face of rainbow trout.
Fish don’t have a complex cerebral cortex - can they still perceive pain?
Fish have areas in the brain for pain perception, emotion, learning, memory, fear, social behaviour. The pallium in the fish is equivalent to the human cortex for feeling pain. Fish brain structures
Fish are cold-blooded - does this stop them feeling pain?
Temperature control in animals has nothing to do with pain perception.
Do anglers harm fish?
Hooks cause harm to gills, jaws, the esophagus, and eyes, inhibiting movement and feeding. Under great stress, many die later, with most deaths occurring some time after release. Angling
If fish cannot feel pain, why do they allow themselves to be caught again?
A hungry fish that is in pain does not cease to be hungry. The motivation to feed overrides the inhibiting effects of pain.
Feeling pain is as vital to fish, as it is to other animals
Pain teaches fish to avoid things that cause harm. Pike, for example, remember to avoid anglers’ hooks, as do carp.
Attacked by a predator, fish may: breathe faster, release alarm pheromones, flee or freeze, try to look bigger, change color. Suspend feeding, or avoid where the attack occurred.
Fish more sensitive to pain in different parts of their body
Russian scientists discovered, in various types of fish, that the most sensitive areas to pain were the tail and pectoral fins, skin around the eye, and olfactory sacs.
Fish give up enriched environment for pain relief
In an experimental tank, zebrafish chose to live where there was gravel and plants, instead of in a barren environment. However when they were injected with a painful chemical they preferred to spend time in the barren environment where there was analgesia in the water.