How Fast Do Goldfish Grow?

So how fast do goldfish grow?

There is no one answer to this question. There are many variables that affect the growth rate of a goldfish. The growth of the goldfish depends on the water quality, feeding, size of the tank and other maintenance in general like the maintenance of water heater, filter, etc.

Goldfish can grow up to 6 inches in a bowl or small aquariums and they can grow even bigger in ponds, up to 14 inches. (Source)

how fast do goldfish grow image

Factors affecting the growth of the goldfish

  • Water temperature
  • Feeding
  • Tank capacity
  • Water Quality

How to maintain a healthy environment for the growth of goldfish

Temperature

Goldfish is a cold-water fish so it does not want a high temperature.

But you should keep the temperature of the water of your aquarium fairly warm about 65 degrees Fahrenheit to 75-degree Fahrenheit.

If the water gets too cold then the goldfish will get into hibernation which slows down its growth.

Feeding

Feeding is very important when it comes to the proper growth of a goldfish.

Goldfish are omnivorous so they can eat other small fishes like guppies and also vegetables and live plants.

Goldfish can even eat the algae. It is actually good nutrition for them. 

This is the reason why the goldfish in the pond grow fast because they get algae to eat where aquarists usually don’t like algae in their aquarium.

You should feed high alkaline and high protein food to your goldfish for their proper nutrition.

Goldfish do not have a stomach so they digest through their intestine, that’s why they required to be fed often.

You should feed goldfish 2 to 3 times a day.

Also, don’t feed them frequently. Maintain a healthy amount of time between the feeding session. Also, maintain a similar schedule for feeding.

It will keep the goldfish energized throughout the day. 

But you should not over-feed the goldfish. A good rule of thumb is feed the goldfish about the size of the eye of the goldfish or feed the goldfish the amount of food it can consume within 2 minutes.

Tank capacity

Tank capacity is one of the factors when it comes to the growth rate of the goldfish.

Goldfish produce a lot of waste that’s why goldfish cannot thrive in small fish bowls. 

Because the small fishbowl gets packed with ammonia very soon.

When it comes to the ideal tank size for goldfish, the more the better!

The ideal size for a goldfish is 20 gallon aquarium tank i.e. 20 gallon per goldfish.

It will provide a lot of space for swimming and ammonia dilution.

But if you are just starting out then you can put maybe two goldfish in a 10 gallon tank but they will not grow till their highest size unless they are placed in a larger tank.

Water

As goldfish are very messy i.e. they produce a lot of waste.

To maintain a healthy aquarium for goldfish you should replace about 25% of the water on a weekly basis and about 50% of the water on a monthly basis.

factors affecting the growth of the goldfish infographic

Conclusion

So, there is not a specific answer to how fast your Goldfish will grow. It really depends on the size of the tank because Goldfish grow to the size of their tank.

But the size of the tank is not the only factor affecting the growth of the Goldfish. The growth of the Goldfish is also depended upon how well you maintain your tank.

FAQ

How long does it take for goldfish to grow?

It really depends on the breed of the goldfish and the environment in which it is kept.

Usually, goldfish can grow from 6 to 15 inches very fast.

If you keep the goldfish in a small bowl or small tank then it will affect the growth of the goldfish i.e. it will grow slowly.

How to grow goldfish faster?

You have to do a few things to grow goldfish faster. 

  • Keep the water temperature of your aquarium about 65 degrees Fahrenheit to 75-degree Fahrenheit
  • Feed high alkaline and high protein food to your goldfish
  • Maintain a good tank size for your goldfish, 20 gallons for one goldfish is sufficient tank size.
  • Make frequent water changes. Change about 25% of water per week and about 50% of the water every month.

How big do goldfish grow?

The growth of the goldfish is really depended upon the tank size in which it is kept.

When you keep a goldfish in a small bowl or small tank then it will grow very slowly and it will not grow more than 6 inches.

Whereas, if you keep goldfish in large tank say 20 gallon per goldfish then the growth will be a lot faster and it can grow up to 14 inches.

How fast do shubunkins grow?

Shubunkins is a breed of a goldfish. It has a life expectancy like other goldfish of about 30 years approximately.

But most of the goldfish don’t live that long.

Around 10-13 years is the average life expectancy of any goldfish.

In this time period goldfish can you grow from 3-5 inches to 12 inches.

Do goldfish grow bigger in ponds?

According to DEC,  when Goldfish are kept as a pet in a small bowl or small aquariums then don’t get bigger than 6 inches but the Goldfish found in the wild, lake or Ponds they can grow bigger up to 15 inches.

However, if you maintain a good size of the aquarium for Goldfish approximately 20 gallons per Goldfish then it will have a lot of space to swim and dilute the ammonia, which results in faster and more growth of Goldfish.

Do goldfish only grow to the size of the tank?

Yes, Goldfish do go grow to the size of the tank. Goldfish are indeterminate growers which means that they can grow until they die. So if you maintain a good environment for the growth of the goldfish then it can grow up to 15 inches. 

How big will goldfish grow in a 10 gallon tank?

If you are just starting out then 10 gallon tank insufficient for  2-4 Goldfish. But it will not reach its highest size. You will have to place them into a bigger aquarium to reach their highest growth size. About 20 gallons per Goldfish is a good rule of thumb. 

The average lifespan of Goldfish is around 10 to 13  years and they are indeterminate growers that mean they can grow until they die.

How big will my goldfish get?

According to DEC when Goldfish are kept as a pet in small in a small aquarium, they can get bigger as much as 6 inches but wild Goldfish can get about 13 to 14 inches long.

But if you maintain a good size of the aquarium for Goldfish, it can get bigger up to 13 to 14 inches even in aquariums.

20 gallons per Goldfish is a good rule of thumb to reach Goldfish to its highest size.

Maintaining a big aquarium does not guarantee a bigger Goldfish, there are other factors as well that comes into play like, water temperature, feeding, water change frequency, etc.

Will my goldfish outgrow his tank?

Goldfish grow to their tank size so it is not likely that your Goldfish outgrow the tank. If you keep Goldfish into a small bowl or small aquarium, then it will not grow bigger than 6 inches.

But if you maintain a good aquarium size about 20 gallons per Goldfish, then it can grow about up to 15 inches.

How long does it take for Goldfish to grow to full size?

The life expectancy of any Goldfish breed is about 30 years, but it is not normal. Usually, Goldfish live about 13 years. 

Goldfish are indeterminate; i.e. they grow until they die. 

If you maintain a healthy aquarium environment for Goldfish, then it can grow up to 15 inches.

Why is my goldfish not growing?

Goldfish grow to the size of the tank. Goldfish kept in a small bowl for aquarium can grow up to 6 inches. For a Goldfish to reach its maximum size, you have to keep Goldfish into a large tank.  20 gallons per Goldfish is a good rule of thumb. 

Also, if the Goldfish does not have a healthy aquarium then it may stop growing. 

The average lifespan of a Goldfish is about 10 to 13 years. Goldfish is an indeterminate grower that means they can grow until they die.

Photo of author
Author
Prathmesh Gawai
He is the main author and editor at Aquagoodness.com. And he loves to share helpful information on aquarium and/or fishkeeping hobby. Prathmesh has over five years of aquarium and/or fishkeeping experience. Currently, he has a Betta fish tank. He has written hundreds of articles on various aquarium fish species and on fish tank maintenance over the last five years. Connect with him on YouTube here. Learn more about him here.

Leave a Comment