Despite their popularity, myths and misconceptions about goldfish abound. The most common myths are that goldfish have short-term memories, thrive in bowls, remain small, have little variety, and are delicate. All of these are untrue, as we break down in this article. In fact, goldfish are actually an incredibly diverse, hardy, and large species of fish that can live quite a long time. There are also many different varieties to choose from, making them ideal for beginners and experts alike.
1. Goldfish Have a Short Memory
One of the most pervasive myths about goldfish is that they have an incredibly short memory of about three to ten seconds. In reality, goldfish are intelligent for fish and can form memories of up to at least three months. Scientists and researchers have conducted several studies debunking this myth. These studies go back pretty far: a study in 1994 proved that operant conditioning was possible in goldfish for at least one week. Interestingly, a study in 2004 actually posited that goldfish have two separate memory systems by testing how brain lesions affect trained behavior. And a 2006 study tested memory impairment in goldfish and found that spatial learning can be negatively affected.
But you don’t have to be a scientist or researcher to test this myth. Goldfish recognize their owners, as do many fish species. You can also test your goldfish’s memory using operant conditioning or training them to perform basic tricks.
2. Goldfish Can Live in a Bowl
Goldfish are a varied species that typically grow between eight and twelve inches in length. As with most animals, the most drastic growth happens during their first year of life. This means that they need an enclosure large enough to accommodate their adult size. As such, the smallest aquarium for a goldfish should be around 40 gallons— much, much larger than bowls.
But size is just one consideration when choosing the best fish tank. Bowls also don’t accommodate filters as well as tanks do, and filters are a must for goldfish. The first reason is because goldfish do not have a labyrinth organ, which functions similar to a human lung. Anabantoids, also known as labyrinth fish, can go directly to the surface of the water and take in air. Other fish, like goldfish, rely on filters to oxygenate the water for them. Filters are also necessary to reduce the amount of waste that goldfish produce, which is significant.
3. Goldfish Stay Small
As noted in the previous section, goldfish can grow up to a foot in length. The largest varieties can even get up to 16 inches in the right conditions. Most people are used to seeing juvenile or infant goldfish in the pet store, when they are just a few inches in length and very slim. In reality, these fish will change drastically in appearance as they grow longer and broader.
It can take several years for goldfish to reach their adult size. Unfortunately, persistent myths and poor care practices often lead to premature death. As such, many people are unaware of exactly how large goldfish grow. The result is that goldfish are one of the most common fish that outgrow tanks.
4. Goldfish Have No Variety
Amazingly, there are approximately 300 distinct breeds of goldfish. The Common Goldfish is by far the most popular (and populous) type of goldfish available in stores. Other well-known goldfish breeds include the Telescope or Moor, Bubble Eye, Comet, Fantail, Ryukin, Oranda, and Ranchu. Some breeds are often mixed up due to their similarities, such as the Ranchu and Oranda and the Fantail and Veiltail.
5. Goldfish are Short-Lived
When properly cared for, goldfish can have a lengthy lifespan of 10 up to 30 years, marking them as one of the longest-lived aquarium fish. This is decades longer than most people expect and represents a serious commitment. Goldfish are actually one of the healthiest pet fish species when kept under the proper conditions. Choosing a healthy juvenile or an ethical breeder can also ensure your goldfish lives its full lifespan.
The myth that goldfish have a short lifespan comes from poor care practices, which often lead to goldfish dying as juveniles after just a few months. Inbreeding and overbreeding in commercial goldfish farming also causes genetic defects that shorten the lifespan of the more popular breeds, such as Common and Comet Goldfish.
6. Goldfish Are Delicate
While goldfish do have specific care requirements, they are comparatively hardy. For example, goldfish are one of the types of fish that do not need a heater and can thrive in colder temperatures (around 68 – 75 degrees Fahrenheit). They are also an ideal pond fish and adapt well to outdoor conditions.
In fact, they are so hardy that they often adapt too well in outdoor conditions. When released into non-native environments, they can outcompete local species and destroy established food chains. Goldfish have voracious appetites and are confident, meaning that they will challenge other fish and predators for the best meals. For this reason, goldfish are considered invasive in many areas where too many domestic pets have been released into ponds and other waterways.
