Pets & Animal Pets Fish

How Do Goldfish React to Mirrors?


    • Goldfish are historically one of the most popular breeds of domesticated aquarium pets. They are inexpensive, relatively maintenance free, and inherently resilient, which adds to their appeal as a family pet. Many owners enjoy the fact that goldfish are social creatures, which makes their interactions within the tank, as well as their response to food and outside stimuli, interesting to observe.

    Intelligent Creatures

    • Despite their small size, goldfish are actually relatively intelligent fish. As evidenced in The Discovery Channel's "Mythbusters," not only do goldfish have the ability to differentiate between sounds and colors, but they also possess a memory span of approximately one month. Interestingly, goldfish exhibit social learning skills, which is evidenced with a fish becoming excited and swimming vigorously when the primary feeder is standing in front of the tank. According to, each individual goldfish possesses his own distinct set of behaviors, with some fish inherently acting in a more social manner than others. Much of their learned behavior can be reinforced through feeding, which becomes an incentive for repetition of a desired behavior.

    Establishing Dominance

    • Goldfish exhibit social behaviors within the tankCouple kissing inside a goldfish bowl love image by Peter Baxter from

      Although goldfish are considered to be intelligent, the way they react to a mirror is primarily based on their inability to recognize that the fish in the mirror is actually their own reflection, as opposed to another fish. Their reaction to a mirror closely mimics the typical social interactions between goldfish while in a school, and it can be exhibited in several different ways. A goldfish may respond in an aggressive manner towards the mirrored image. According to, this is a standard behavior pattern shown when a new fish is introduced into an aquarium setting. The older fish may nip at the new arrivals, showing his dominance over the tank. Typically, this type of behavior dissipates once the new arrival has settled into the established social structure of the tank.

    Cautious Acceptance

    • A second common reaction is is for the goldfish to simply swim away from the mirror, effectively ignoring the other "fish" in the tank. This type of behavior is shown, according to, simply because the goldfish has not noted the presence of the mirror in the tank. Once the goldfish realizes that the mirror is present and sees another image, he often remains stationary in front of the mirror, scoping out the other fish within his view.

    Welcoming a Newcomer

    • Goldfish are social animals that enjoy having other fish in the tank, and a common response to a mirror is for the fish to slowly draw near and then pull away. This may be done many times, with the culmination being that the fish will then gently prod the mirror, as stated on This exhibits a symbol of acceptance between the goldfish and the mirrored image, and the goldfish welcomes her perceived new arrival into the tank.

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