• Canadian researchers used the African Cichlid (Labidochromis caeruleus) for their experiment. It is commonly called an "electric yellow." (Photo: Erica Ingraham)

Do you ever wonder if your pet fish remembers you after you walk away from the tank? Chances are it probably does.

Contrary to the popular belief that a fish's memory spans less than a minute, Canadian scientists believe the African Cichlid, a common aquarium fish, can remember up to 12 days.

Researchers from MacEwan University in Edmonton are looking into the memory time periods of fish. Fascinated by the African Cichlid, a fish known for being clever, they decided to test its limits.

“Fish do not get the benefit of the doubt in the animal kingdom,” says Trevor Hamilton, the lead researcher of the team at MacEwan University.

During testing, each fish was trained to enter a particular zone of an aquarium to receive a food reward. “We did the training for each fish three times in a five-day period for 20 minutes,” Hamilton says. The fish were then given a 12-day rest period in another aquarium.

Once re-introduced into the testing aquarium, researchers discovered the African Cichlids went back to the same zone associated with the food reward. “They remembered where the food used to be.”

The experiment was repeated using a different zone of the aquarium. After 12 days, the fish were going to the new part of the aquarium.

Hamilton says this experiment demonstrates fish are capable of remembering for a long period of time and can learn new things.

Now that the research team can test the cognitive abilities of fish, they plan on understanding what alters their memories, including whether environmental changes like fluctuating water temperature and increases in carbon dioxide have any effects.

“We can now use this method of testing memory to understand our changing ecosystem,” Hamilton says.