Accessibility links Whilst the creatures can clearly be seen to react to a jab or blow, experts have disagreed over whether the reaction indicates
a sensation of pain, or is little more than a basic reflex. The academics, from Norway and the US, say their finding undermines claims that fish merely display reflex actions and do not sense pain. “The results show that it could not have been a simple reflex action,” said Dr Joseph Garner. “The fact that their behaviour changed so much really strongly suggests there is something going on with their memory and experience of that event that is not a reflex. I believe it does show that fish feel pain.” For the experiment, each fish was fitted with a miniature jacket containing a tiny flexible foil heater similar to those used in the aerospace industry to keep wires and electrics dry. The heaters had an upper safety limit of 50C to prevent harm. Both groups of fish &ndash those given morphine, and the control group which were injected with inactive saline solution &ndash showed a similar “escape response” when the heater was turned up to around 38C, equivalent to a fairly hot bath.
As soon as the behaviour was noted, the heat was turned off to prevent suffering.