Goldfish Facts: our top facts about goldfish

We love fascinating goldfish facts here at The Goldfish Tank – and there really are some weird and wonderful facts about goldfish!

Top goldfish facts

Check out the amazing goldfish facts below to better understand your fish. The more you know about goldfish, the better you will be able to care for them!

Goldfish don’t have stomachs

Goldfish don’t have stomachs and should therefore be fed easily digestible food in lots of small feeding sessions, rather than lots of food at once. This is also why goldfish produce so much waste and why you need a filter to keep their water clean.

Goldfish have been known to live for over 40 years

With the proper care, goldfish can live for decades. This goldfish was said to be 45 years old. 

The collective noun for goldfish is “a troubling”

Just like you’d say “a herd of cows”, you’d say “a troubling of goldfish”!

Goldfish can recognize peoples faces

Goldfish can tell different faces apart and are able to distinguish between different shapes, colors and sounds.

Goldfish have a memory-span of at least three months

Many people say that goldfish have a memory of just a few seconds, but this is a myth! Goldfish have a memory span of at least three months!

Goldfish can grow to over a foot long

Goldfish can be stunted by being kept in tanks that are too small for them and where the water quality is poor. This means that they don’t reach their full potential size. However, goldfish can grow to be over a foot long when kept in the right environment.

Selective breeding has led to a huge variety of goldfish shapes and colors

Humans have bred many different varieties of goldfish.

Goldfish can’t close their eyes

Goldfish have no eyelids, so they have to sleep with their eyes open!

Goldfish have been kept as pets for over 2000 years

Keeping pet goldfish dates all the way back to ancient China!

Goldfish can see more colors than humans can

Goldfish don’t like to be kept in the dark and, unlike humans, they are able to see ultra-violet and infra-red light.

Goldfish don’t urinate

No fish urinate. Instead of expelling ammonia by urinating (as mammals do), fish filter ammonia from the water using their gills.

Goldfish can live in very cold water

The metabolism of a goldfish will slow down significantly in cold water, almost like they are hibernating. This means that goldfish can survive in very low temperatures, sometimes even in ponds that have frozen over for the winter!

Goldfish and Koi are NOT the same species

Goldfish and Koi are both members of the carp family, but they are not the same species. They can interbreed but their offspring will be sterile.

Goldfish lay a lot of eggs

A female goldfish will lay hundreds or even thousands of eggs in a single spawning. However, only a small proportion of these will be fertilised.

It’s possible to breed goldfish and care for baby goldfish in a home aquarium.

Goldfish change color depending on light levels

If your goldfish is kept in the dark at night, you may notice that its color appears faded when you switch the aquarium light on again in the morning. Also, goldfish kept outdoors with greater exposure to natural light are usually more colorful than goldfish that are kept indoors.

Goldfish are omnivores

Goldfish will eat plants, insects, small crustaceans, and sometimes even other small fish! We have several articles on goldfish food!

Goldfish have been available in Europe and the US for a long time

The domestic goldfish originated in China, but was introduced to Japan in 1603, to Europe in 1611 and to North America around 1850.

Goldfish were once traditional anniversary gifts

In the early 17th century it was traditional for men to give their wives a goldfish on their one-year anniversary! This was meant to symbolise a prosperous future, but the tradition died out when goldfish became more readily available.

Touching a goldfish can endanger its health

You should never pet your fish, as you may damage the slime coat that protects its skin from infection.

Goldfish get used to being around humans

Goldfish can get used to humans and will eventually stop considering them a threat. This can make it possible to feed your goldfish by hand!

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