Fish Have Long-Term Memory, Can Remember Food Source Even After 12 Days

African Cichlids, a popular aquarium fish species, has a long memory. Researchers have found that the fish can remember the location of a food source after a 12-day gap.

The study was conducted by researchers at the MacEwan University in Canada. According to the team, the fish's ability to store long-term memories could be an evolutionary advantage.  

"Fish that remember where food is located have an evolutionary advantage over those that do not" said lead scientist Dr Trevor Hamilton. "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 to that area. Decreases in the availability of food would promote the survival of species that can remember the location of food sources."

Animals such as chimpanzees, elephants and even dolphins are known to have long-term memories. Most researchers believe that fish memories last for about 30 seconds or so. Hamilton decided to see if African cichlids (Labidochromis caeruleus) could store memories from 12 days before.

African cichlids are popular aquarium species and are known to display complex behaviors, such as aggression. "There are many anecdotes about how smart these fish are" Dr Hamilton said in a news release. "Some people even believe that their cichlids watch television with them."

In the study, researchers trained each fish to find food in a particular area of the aquarium. The training lasted 20 minutes each day and was given on three consecutive days. After 12 days, the fish were reintroduced in the training area, where their movements were recorded. Researchers found that fish were more likely to search for food where they were fed 12 days ago.

In the next part of the study, researchers trained fish to locate food using a different stimulus. The research showed that the species of fish had a robust memory.

Researchers will now be investigating whether or not environmental factors or drugs can alter the strength of fish memory.

Cichlid fish are known for their rapid evolution, according to The Telegraph. Thousands of new species of the fish have evolved over the last 12,400 to 100,000 years.

Last year, a different set of researchers had shown that goldfish have a fine taste in music. The team found that goldfish can differentiate between Johann Sebastian Bach and Igor Stravinsky.