How Big do Goldfish Get?


There is no fish in the aquarium better known than the goldfish. Popularly, this type of fish is often associated with the “golden fish” from anecdotes. And he has all the reasons to be so.  Metallic orange coloring turns this fish into a real adornment in any type of aquarium.

How big do goldfish actually get? Some people say they can grow as large as the fish tank! But that is not true, usually, if kept in the right conditions, a goldfish can reach the size of 12 to 14 inches. That is for the common species.

There are, however, some species of goldfish that won’t grow larger than 6 inches and there are some that can get way bigger.

It all depends on the aquarium and how much time you spend with your fish. Goldfish don’t require any special heating in their tank so you can take that down of your list.

The only thing that you need to care for is a good filtration system. They can get very messy. We have a section dedicated to that a few paragraphs below, so keep on reading.

Even if everyone recognizes and interacts at least with him, there is much to say about this extraordinary aquarium fish. Below we will give you some curiosities and other great info about the goldfish.

How big do common goldfish get?

As with most species on this planet, genetics play a big role in the development of one’s size. Goldfish benefit from that thing too. The common goldfish can reach a size of around 10 inches. This is true for most common types of goldfish that are sold in aquarium shops.

If you are looking for goldfish that can be put in a pond, those can reach a size of 18 inches. They are big. They eat a lot!

What are the types of goldfish that get large in size?

The biggest of the fish tank goldfish are the Black Moor and the Oranda goldfish. They can reach sizes up to 11 inches in a very short time. They are available at most aquarium shops and they are very easy to care for.

How long does it take for a goldfish to reach maximum size?

This depends on the tank they are kept in. Usually, it doesn’t take long for them to grow to a full 6-10 inches. If they are kept in a big tank, with plenty of food, they will get that in a very short period of time. But if they are kept in a small tank or a fishbowl, they will grow much more slowly.

Can you make your goldfish grow faster?

The best way to do this is to ensure that he gets the best care ever!

When people think of goldfish, they think of a fish that they can feed once a day and everything will be fine. That is not true! Like with every other fish, goldfish need to be looked after. If you properly care for it, it will grow to its full potential.

Always look after the water quality. Goldfish tend to be very messy and they require a good filtration in their tank to keep the water clean. Remember that nigh nitrate and ammonia levels are harmful to the fish.

How big goldfish get in the wild?

To date, the longest goldfish was 18.7 inches. The fish belonging to a lady from the Netherlands has never been weighed, so its mass remains unclear.

A goldfish caught in Michigan, however, measured 15 inches and weighed 3 lbs, so assuming that Dutch behemoth weighed more than 3 lbs is safe. Typically fancy goldfish grow up to 8 inches, while single tail goldfish grow up to 10 and sometimes up to 12 inches long.

Attaining the monstrous sizes recorded in the Netherlands and Michigan is rare for domestic goldfish; these fish were exceptions to the norm.

Black Moor Goldfish

How do you care for your goldfish?

The aquarium must be equipped with a filter, water pump, light, etc. The necessary biological conditions in the aquarium are only possible with a technical endowment.

There is no need for heating, the goldfish being the descendant of the silverfish, of old China, being a cold water fish. When it’s very hot, the water needs to cool down. More: Do Goldfish Need a Heater?

On the bottom of the aquarium lay large gravel (the size of the walnuts). When choosing aquarium plants, choose the cheapest ones, because sooner or later the goldfish will eat them.

One-third of the water needs to be replaced twice a day because these fish leave much mucus. The exchange of water should be just cold. You have to feed them daily and you have to take care of the quantity.

Give them as much as they can consume in 5-8 minutes because the leftovers left in the aquarium can create many problems. You can give them living or dry food, but natural food should be bigger

The plants with roots and strong leaves are rarely suited, possibly in pots, especially in the case of large carriages, with veil fins, which require a very large swim.

This is why a garden heel is preferred for this species of the goldfish, which feels shaken in a room aquarium. The goldfish feels much better in the bush, it multiplies better and the number of juveniles is higher. Not requiring special conditions, he grows harmoniously.

The golden carp, also known as goldfish, is one of the most popular ornamental fish. As it grows, both in size and age, it manages to live in captivity for more than 10 years. It does not need special care, being easy to maintain.

It needs a lot of space

If you’ve decided to buy a goldfish, do not put it in a bowl. It does not sit in a small glass bowl, as we have seen in cartoons or in old Hollywood movies, but in a large, well-ventilated and neat aquarium.

To grow, goldfish carriages need a 5-gallon tank. As they grow, they have to offer them an ever larger aquarium. You can decorate it with very large rocks and decorative plants.

Make sure that the water temperature in the aquarium is between 18-21 degrees Celsius. Maintaining heat is done using a fluorescent lamp. Keep it on for at least ten hours a day.

Even if golden fish oxygenate their own water, your aquarium must also have an oxygen pump. It is advisable to use a fine sand substrate because the goldfish is wont to seek food through the sand. If you use gravel, you might get hurt.

Feed it with extra care

To grow, the goldfish must eat at least twice a day. It is good to give him equal portions of food so that in the aquarium there will not be leftovers. They can dirty and contaminate water with algae and bacteria.

The goldfish are omnivorous, that is, it eats both meat and vegetal. Give him special food for the carps, and from time to time, please him with peeled and peeled peppers.

More: Lionhead Goldfish Care

Keep your aquarium clean

A filter will help you eliminate the impurities in the water. In this case, you only have to change half the amount of water in the aquarium weekly.

If you want to replace everyone, make sure you have another container to move the fish. Before it refills, boil water from the tap and leave it overnight to decant. This eliminates chlorine and other harmful substances.

The goldfish may change color

An interesting thing about goldfish is that, over time, it can change its color, becoming gray in the presence of insufficient light. So make sure the aquarium has light if you do not want the little man to get another color.

What can I feed my goldfish?

In nature, the carafe feeds on insects, crustaceans and plant matter. In captivity, I can offer a very wide range of foods: flakes, granules, floating puddings, and frozen food. Carnation has more carbohydrates and less protein.

Goldfish raised in captivity eat all the time and can not stop. This can lead to over-interference and intestinal problems such as occlusions.


Can I touch my goldfish?

Like all fish, the goldfish should not be touched. In fact, by touching a fish, we can endanger our health because touching it damages the mucus, the protective layer, exposing the skin to bacteria or parasites.

However, goldfish respond to people by arriving on time to eat and can be taught or acclimated to take the food from the human hand. The “reputation” of fast-dying caraways is often due to poor care. The lifetime of a captive Goldfish may be 15-18 years.

If you are left in the dark for a while, the goldfish gradually change their color until they are almost gray. Goldfish produce pigment in response to light in a way similar to how human skin tan in the sun.

Pisces have certain cells, called chromatophores, cells that produce pigments that reflect light and color the fish. The color of a goldfish is determined by the pigments that are in the cells, how many pigment molecules are there and whether the pigment is grouped inside the cell or is staggered over the cytoplasm.

Because goldfish eat live plants, their presence in a planted aquarium can be problematic. Only a few species of aquarium plants, such as Cryptocoryne and Anubias, can survive around the caraway, but they require special attention so they are not spoiled.

Plastic plants are often more durable, but their hard branches can irritate or affect the skin of the fish that touches them. So, in the aquarium, we will not plant many plants, and for the varieties of honeycomb, it is good to set up the higher aquariums in order to capitalize on the beauty of the tail.

Behavior and breeding of the goldfish

Goldfish is a peaceful fish that does not aggrieve other fish. However, it is possible to swallow very small fish. It can be put with other species as long as they tolerate the lower temperature they are in. It is not recommended in planted aquariums because they have the habit of deforestation and eating plants.

Goldfish is known for its ability to learn and recognize people. The memory of a Goldfish is an average of 3 months. Because distinctive shapes of colors and sounds can be trained to make various tricks.

There is no sexual dimorphism at the hands. During the reproduction ritual, generally after a temperature drop, the males fled and drove the females carrying the eggs by encouraging them to lodge. Fertilization takes place externally. Fertilized eggs are sticky and adhere to plants or objects.

Incubation lasts for 48-72 hours, and the vitellin bag is resuspended in approximately one week after the final form. Alevins do not have adult-specific color and are silver-gray. Color develops between a few months and a year. If they are not exposed to light the pigments are lost and the fish becomes gray.

Here are some things that people get wrong about goldfish

1. The goldfish can be held in the bowl

For years, the goldfish was promoted as the perfect fish for the bowl, and all of its appearances in the media are in this form. In reality, the glass bowl is a jail for life for the liked fish, a condemnation to the safe and slow death.

In such a limited space, there is no aeration, filtration, the volume of water to dilute toxic compounds, and bacteria and ammonia quickly capture the entire aquatic environment, making survival impossible.

For a fish of the size and the character of the goldfish, a spacious aquarium of at least a few tens of liters is the ideal home.

2. Goldfish grow just as much as the size of the aquarium

There is a sense of truth in this statement, but not as innocent as it sounds and has more to do with water quality than with the size of the aquarium.

Under normal living conditions, in a healthy aquatic environment, the goldfish ay continues to rise to death. In a small aquarium, water parameters deteriorate rapidly and the quality of life decreases.

The stopping of the goldfish is a negative sign of the disease and the suffering of the fish. Because of this many fish are deformed and die at young ages.

3. The goldfish has a 3-second memory

It is often said that the goldfish can be kept in the bowl because it has a short memory, and to the other end of the vessel has already forgotten what it saw and on the return, everything will look new.

This myth was probably born as a justification for bowel maintenance. In reality, goldfish have a very good memory, lasting up to 5 months.

They can perceive the passage of time and can devote themselves to a routine (for example, they anticipate when they will be fed in the morning). Some copies can be trained.

4. The goldfish produces more waste than any other fish

Referring to the amount of manure per body mass, the goldfish do not produce more misery than other aquarium fish. A large fish is normal to produce more residue than a minion. The amount of residue is closely correlated with the quality of the feed the fish receive.

5. The goldfish live a little

In fact, the goldfish is one of the longest-lasting fish of the aquarium. In an optimal aquatic environment, goldfish live on average for 20 years. The longevity record of a golden aquarium was 49 years old.

The fact that many goldfish die quickly is the consequence of the poor living conditions and not the life expectancy of this species.

6. The goldfish and koi carps are the same species

Although closely related and even hybridized, they are not the same species. Koi pieces (Cyprinus carpio) is an intensely selected variety of common carp, while golden carps are the domesticated descendants of Carassius carassius. Both belong to the same Cyprinidae family.

7. The goldfish need cold water

In fact, the goldfish can live as well in both cold water and warm water: from just over 0° to almost 40°C, which is confirmed by their spreading into natural habitats all over the world. However, because warm water retains less oxygen, it is advisable to keep the fish in the water at room temperature.

8. The goldfish cannot be held with other fish

Goldfish are not anti-social and aggressive, nor does it produce toxins that kill other tropical fish. The goldfish can be kept together with other species as long as they share the same water parameters.


In conclusion, the carp was, is and will remain a popular fish because it is easy to grow in large aquariums and ponds, it is very adaptable, it is not aggressive and is easy to reproduce. It is our responsibility to ensure a minimum of conditions.

Saurabh Kumar

I am a passionate fish keeper, with years of experience. You will find some really useful tips and information on this blog about Freshwater Aquariums.

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