Fish brain? No, goldfish are a lot smarter than we think

Their brain power is at best shallow – or so we thought.

Fish have hidden depths and could be a lot smarter than we think, say scientists who have busted the myth fish have a three-second memory span.

In fact, they can recall information for up to a fortnight, a study shows. Scientists trained African cichlids, a popular aquarium fish, to eat in a particular part of their tank – and found they returned there to be fed after a two-week break.

The findings prove fish are actually quite brainy, say researchers.

And their memory span gives cichlids an advantage over other species, said Dr Trevor Hamilton of the MacEwan University, in Edmonton, Canada, who carried out the experiment.

‘Fish that remember where food is located have an evolutionary advantage over those that do not,’ he said. ‘If they are able to remember that a certain area contains food without the threat of a predator, they will be able to go back there.’

In tests, each fish was allocated a zone of the aquarium to be fed in.

Each training session lasted for 20 minutes and the cichlids ate in their area for three days. The fish were then given a 12-day rest period before being reintroduced to the training area and their movements, recorded with motion-tracking software, found the fish returned to the spot where it found food.

Researchers are now investigating if fish memory is affected by environmental conditions, the Society for Experimental Biology reports.