Do goldfishs have a memory of 3 months or 3 seconds?

There are many theories on the topic. Some claim that the memory of a goldfish is only 3 seconds, some one month, and some as long as three months.

The notion that goldfish have a memory of only 3 seconds is thought by some to be a myth, developed by pet shop owners to convince buyers that the small fish tank environment was not cruel treatment of their pet. Others claim that goldfish have been placed in mazes and have shown to remember only 3 seconds of the maze, thus the 3 second memory theory.

The first fundamental problem is that we cannot differentiate a goldfish's memory from it's indifference, or it's ability to swim through mazes. Unlike other domesticated animals, goldfish will swim to the glass of the tank no matter who comes to it; owner or feline.

If you have ever had a fish tank, your goldfish will recognize movement outside the tank in association with their food source. This memory certainly lasts longer than 3 seconds. I don't recommend this test for seeing how long this memory lasts - the results may be fatal to the goldfish.