Do fish really forget everything in three seconds?

Anyone who keeps an aquarium has probably heard that fish have a three-second memory. I read a breakdown of this myth, and it turned out more interesting than I expected. According to the author, there is no scientific evidence behind the "three seconds", and it's hard to find an experiment that established it for goldfish. Versions of the claim even mention two, ten and thirty seconds, which is suspicious in itself.

Fish can hold information for days, months, and sometimes longer. The article gives an example: rainbowfish were trained to find an escape route in a special apparatus, and 11 months later they still did it faster than at the start. Goldfish were trained to swim exactly 70 centimeters along a long tank, and after the cue was removed they kept judging the distance quite accurately from the surrounding space.

What struck me most was the part about owners. We can't say with confidence that every pet fish recognizes its owner's face, but archerfish in a well-known experiment learned to pick a familiar face out of dozens of images. Most likely, aquarium fish remember silhouettes, movements and feeding times. Goldfish were conditioned to receive food at a set hour, and they became active before feeding time for several days even after the feeder stopped delivering food.

My takeaway is simple: fish are smarter than we usually assume, so it's worth making the tank interesting for them, not just pretty for us.

Source: Hi-News.ru