"We are told that a goldfish has a memory span of less than three seconds and that no matter how small its tank is, it will always discover new places and objects," Rory said. "I wanted to challenge this theory as I believe it is a myth intended to make us feel less guilty about keeping fish in small tanks."

Rory's experiment involved teaching a small group of fish to swim to a beacon by establishing a memory connection between the beacon and food. Over a period of three weeks, he placed a beacon in the water at feeding time each day, waited 30 seconds and then sprinkled fish food around the beacon. The time taken for the fish to swim to the beacon reduced dramatically, from more than one minute for the first few feeds to less than five seconds by the end of the three weeks.

Following the initial three-week period, Rory removed the beacon from the feeding process. Six days later, he once again placed the beacon in the water and despite not seeing it for almost a week, the fish swam to the beacon in 4.4 seconds, showing they had remembered the association between food and the beacon for at least six days.

"My results strongly showed that goldfish can retain knowledge for at least six days," Rory said. "They can retain that knowledge indefinitely if they use it regularly." Rory also conducted a number of sub-experiments which showed that goldfish were capable of negotiating a simple maze, having them move onto a second beacon if they found no food at the previous one.

"My experiments showed that goldfish have the mental capabilities to learn and remember fairly complex concepts and they can retain that knowledge for at least a number of days," he said. Australian Science and Mathematics School principal Jim Davies said the series of experiments were an excellent example of science investigation made fun.

AAP