Fishy tales from the Aquarium

Fish don’t make noises or contort their faces to show that it hurts when hooks are pulled from their mouths, but a Purdue University researcher believes they feel that pain all the same – and what’s more, their reactions to it are much like that of humans.
Garner and Janicke Nordgreen, a doctoral student in the Norwegian School of Veterinary Science, attached small foil heaters to the goldfish and slowly increased the temperature. The heaters were designed with sensors and safeguards that shut off the heaters to prevent any physical damage to a fish’s tissue.
Half of the fish were injected with morphine, and the others received saline. The researchers believed that those with the morphine would be able to withstand higher temperatures before reacting if they actually felt the pain. However, both groups of fish showed a response at about the same temperature.
Upon later observation in their home tanks, however, the researchers noticed that the fish from each group were exhibiting different behaviors.
“The fish given the morphine acted like they always had: swimming and being fish,” Garner said. “The fish that had gotten saline – even though they responded the same in the test – later acted different, though. They acted with defensive behaviors, indicating wariness, or fear and anxiety.”
Nordgreen said those behavioral differences showed that fish can feel both reflexive and cognitive pain.
“The experiment shows that fish do not only respond to painful stimuli with reflexes, but change their behavior also after the event,” Nordgreen said. “Together with what we know from experiments carried out by other groups, this indicates that the fish consciously perceive the test situation as painful and switch to behaviors indicative of having been through an aversive experience.” [Via]
So, the next time around, treat them more humanly – they feel pain as much as you do.

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