Any fish owner that has been involved in the care and raising of their fish can tell you that they have a memory far greater than the mythical “3 second memory.” In fact, fish have so great a memory that it may have impacts as far reaching as the fish farming industry! Fish have mastered the art of marketing, the idea of “survival of the fittest,” and are even able to be manipulated with operant conditioning.
Despite the example set by Dory from Finding Nemo, fish are capable of rather impressive feats of memory and have been shown to recall information up to five months after being introduced to stimuli. This has far reaching implications for the farming industry. They have discovered that after training fry for a month to respond to a sound, they could release the fish into the oceans to live normal lives out in the seas. Four to five months later, they could play the same training sound and the fish would display the same response – in the case of the fish trained to respond at feeding time it meant that those fish that survived life in the ocean returned to the same place for food as they had when they were fry. If this can be successfully implemented, it means that many of the negative impacts of fish farming can be avoided by letting the fish develop in the wild and then calling them home when it’s time to harvest.
Is it surprising, then, that fish are able to recognize predators and prey? It is not at all unheard of for a fish to recognize a previous predator. After all, carp will avoid a fisherman’s hook for up to a year if they escape!
Perhaps the most interesting impact that fish memory has is their ability to morph prior knowledge into excellent marketing skills. Take, for example, cleaner fish, those fish that survive by nibbling parasites off larger fish that would normally be seen as predators. These cleaner fish have been observed in their natural habitat to “market” themselves to potential clients. While in the midst of cleaning a current client, they will improve themselves if a larger client is in the vicinity in the hopes that their “superior” cleaning skills will encourage the larger patron to visit their cleaning station rather than that of their competitor.
While their memory is not up to the same level as that of humans, fish can certainly compete in the memory market. With patience and determination, you can even “train” your fish to respond to a command or two.