Ryukin Goldfish 101: Care, Size, Lifespan, Food & More

Ryukin Goldfish are a popular goldfish species that have quite a unique look!

Despite this, they’re actually quite active and are a lot of fun to spectate. These fish are also very easy to care for (unlike a lot of other species).

This guide will teach you everything you need to know about Ryukin Goldfish care. By the time you’re done reading it, you’ll be ready to own one yourself!

Species Summary

The Ryukin Goldfish (scientific name: Carassius auratus) is one of many fancy goldfish varieties. It’s a beloved fish species that has a long history in Asian culture.

The exact origins of the Ryukin Goldfish have been long lost to history. However, it’s believed that they originated in China and was brought to Japan in the 1770s. There, the fish became widely popular. It’s even mentioned in early literary works!

Today, the Ryukin Goldfish continues to be an iconic image for Asian heritage. However, fish keepers around the world can enjoy what this species has to offer, too.

It’s widely bred throughout the world. Thanks to its beauty and cold hardiness, these fish can be found in nearly every climate.

Average Ryukin Goldfish Size

The average Ryukin Goldfish size is usually about six to eight inches long when healthy. However, it’s not uncommon to see specimens bigger than that.

Like many other types of goldfish, the Ryukin is capable of growing slightly bigger when kept in a spacious habitat. Those housed in outdoor ponds can sometimes get as big as 10 inches in size!

These fish have a reasonably fast growth-rate, making it important for you to be prepared for where you’ll keep them as adults.


The lifespan of a Ryukin Goldfish is dependent on many factors. While they are hardy creatures, these fish are not immune to stress and disease. A poorly maintained environment can shorten their lifespans dramatically.

On the other end of the spectrum, impeccable care can increase their lifespan. On average, the lifespan of Ryukin Goldfish is between 10 and 15 years.

However, it’s possible to see these fish exceeding 20 years of age! This is definitely a rare occurrence though.

Author Note: Maximizing their lifespan is all about providing the best care possible. When these fish are kept in larger habitats with perfect conditions, they can live well past their expected range.


Ryukin Goldfish are one of the most beautiful goldfish species around. As we mentioned earlier, these fish belong to a subset of fish dubbed “Fancy Goldfish.”

Essentially, that means that they were bred extensively in Asia to achieve the final look we have today.

These fish have a very unique profile. They’re egg-shaped! The body is short and stubby, and the belly is quite round as well.

On top of the body, Ryukins have a large dorsal hump. It connects the head to the rest of the body. When you combine the height of the dorsal hump with the rounded shape of the belly, you get a very interesting look.

These two extreme features make the head have a somewhat pointed shape.

One Ryukin Goldfish swimming in a freshwater aquarium

The tails of these fish are unique, too. They’re double-finned fish. Rather than your basic caudal shape, you will notice that these fish have four tail lobes. This creates a stunning appearance that you won’t see outside of the goldfish family.

Ryukin Goldfish can be either short-finned or long-finned. Long-finned varieties tend to be more sought-after due to their flowing double caudal fins. These varieties also take on a more vibrant hue.

Speaking of color, Ryukin Goldfish are actually available in a wide variety of colorations. You can find red, white, calico, and even chocolate-colored fish. Tri-colored specimens are common as well. They take on hues of orange, white, and black.

Ryukin Goldfish Care

Ryukin Goldfish care is actually considered to be a bit easier than many of the other fancy goldfish species out there. They’re quite hardy and adapt well to any aquarium that’s fully cycled and well-maintained.

Of course, there are some guidelines you need to follow. Contrary to popular belief, goldfish are not tropical fish! They can’t be kept in the same warm waters as most freshwater species in the aquarium trade.

These fish have many different needs that you’ll need to address.

Tank Size

Before you do anything, it’s important that you buy an appropriately-sized tank. With the comparatively large size of Ryukin Goldfish, it would be reasonable to assume that these creatures would need massive tanks.

However, that’s not the case.

A single Ryukin Goldfish only needs a tank that can hold 10 gallons. That’s the bare minimum though, and we always recommend going bigger if possible.

Author Note: A 20 to 30-gallon tank is far better for these goldfish. With an aquarium of that size, you can keep a sizable group together while still giving the fish plenty of room to explore.

Water Parameters

So, let’s talk about water conditions! If you have some experience keeping freshwater fish, you’re probably used to standard tropical conditions with warmer waters. That’s not going to cut it for Ryukin Goldfish!

This is a cold water fish that thrives in temperatures that are a bit lower than normal. Pick up a tank thermometer and use it frequently. This is especially important if you live in a colder climate.

Here are some basic parameters you must follow when caring for a Ryukin Goldfish:

  • Water Temperatures: 64°F to 72°F
  • pH Levels: 6.0 to 8.0 (somewhere in the neutral range is ideal)
  • Water Hardness: 5 to 19 dGH

While they can do fine in temperatures as low as 64 degrees, you’ll need to use an in-tank heater if ambient air temperatures dip below that (this all depends on your setup).

Highly oxygenated water is essential as well. To achieve this, you’ll need to use something like an air bladder to keep your fish in good shape.

What To Put In Their Tank

You have a lot of flexibility when it comes time to decorate the aquarium. Unlike other species, Ryukin Goldfish don’t need a natural environment to stay happy.

They do fine with artificial ornaments and outlandish style.

Start with a medium-sized gravel substrate at the bottom of the tank. Feel free to use whatever crazy color you want. Just make sure that the gravel is rounded and soft.

Now, add decorative hideouts and anything else you want to use to spice up the environment. One of the best forms of decoration you can use is artificial plants.

Real live plants aren’t good for Ryukin Goldfish. They have a knack for uprooting plants and ruining decorations. It’s best to use soft silk plants instead.

The silk plants will provide some shelter for the fish while preventing accidental injury.

A sketch of a Ryukin Goldfish

Speaking of which, that’s one of the most important things to consider when choosing decorations. These are delicate fish with unique fins. Something as simple as a sharp corner on a decorative house can cause injury.

Eventually, that simple injury could lead to infection! Examine all of your decorations and make sure that they’re sturdy, rounded, and safe for your fish.

As for tank equipment, use your best judgment. Implement a heater if you live in a climate that needs it. The same goes for an air pump and bladder. If you have a powerful filtration system, you may not need extra oxygenation.

Your filter should be powerful enough to cycle the tank efficiently. These are messy fish that produce a lot of waste. In addition to standard filtration, we recommend performing 25 percent water changes every week.

Common Possible Diseases

Thanks to their unique shape and biology, Ryukin Goldfish are susceptible to a range of ailments. Swim bladder disorders and dropsy, for example, are fairly common.

The intestinal tract of this fish isn’t the most effective. It has some dead zones where food gets stuck. This leads to constipation.

If the issue isn’t addressed, the swim bladder will be affected. Eventually, the fish will have a difficult time swimming or even staying upright! Fortunately, this problem can be treated naturally with peeled green peas. It’s a natural laxative for the fish.

Of course, Ryukn Goldfish can experience standard freshwater fish diseases like Ich, fungal infections, and bacterial infections. Most of these problems are directly caused by poor living conditions.

Sometimes these fish will start to turn white or possibly even black if they’re suffering from one of these diseases. Keep an eye out!

Author Note: Staying on top of your tank conditions is the best way to avoid disease altogether. If one of your fish does fall ill, quarantine them and turn to over-the-counter medications for treatment.

Food & Diet

Feeding a Ryukin Goldfish is pretty simple. These fish are omnivores that will readily accept most foods.

High-quality dry flakes and pellets should be their primary food source. Daily feedings of commercial food will ensure that your fish are getting a balanced diet.

If you want to supplement that meal, you can provide live or frozen foods periodically, Ryukin Goldfish enjoy bloodworms, Daphnia, brine shrimp, and more.

Regardless of what you feed your fish, do not provide too much! These fish are prone to overeating, which will just agitate their sensitive intestinal systems. Spend some time learning how often to feed them to avoid this problem.

Behavior & Temperament

Despite their egg-shaped body, these fish are not afraid to be active. They’re much more vigorous than other fancy goldfish and can be a joy to watch.

However, it can also prove to be a problem with other fish. Ryukin Goldfish are considered to be semi-aggressive. They will pick on weaker breeds or chase after fish that they could theoretically eat.

As a result, you’ll have to be careful about what tank mates include in the tank.

Tank Mates

Ryukin Goldfish are lively fish that do best in groups. They can be kept singly without any issues. However, they tend to be more confident and outgoing when fish of the same species are around.

As for other species you might want to keep with the Ryukin, stick to other dual-fin fish. Ryukin Goldfish have been known to show some signs of aggression towards faster single-fin varieties.

Choose similarly-sized fish that are non-aggressive. However, they should be tough enough to defend themselves if the Ryukin starts something. Weaker fish, such as Celestial Goldfish and Bubble Eyes, are out of the question.

Give these tank mates a shot:


Ryukin Goldfish are very easy to breed in the right conditions. If you do things right, you can end up with thousands of baby fish to care for!

The best way to breed these fish is in groups. They’re social creatures and do better when multiple males and females are left to spawn.

Create a separate breeding tank that holds at least 20 gallons. Implement fibrous plants with tons of leaves. You can use plants like Anacharis. Or, you can use an artificial breeding mop.

Several weeks before breeding, separate males and females. As spawning time gets closer, increase your feedings of high-protein foods to get the fish in a good mood.

Introduce your fish and let them acclimate before slowly dropping the temperature to about 60 degrees Fahrenheit. Once you’ve reached that target temperature, gradually increase the water temperature by about three degrees per day.

Continue feeding live or frozen foods until the fish spawn.

When they do, you’ll notice the female swell up with eggs. She’ll then lay upwards of 10,000 eggs in the plants and spawning mop.

Immediately remove the adult Ryukin Goldfish. They will start eating the eggs after breeding.

Eggs will hatch in four to seven days. Provide some powdered fish fry food until they are big enough to accept baby brine shrimp            

Time To Use Your Knowledge

Now that you know the fundamentals of Ryukin Goldfish care, you’re ready to keep one in a home aquarium.

While their interesting look might make this species seem intimidating, they’re actually the opposite! These are very easy fish to own as long as you meet their essential requirements.

If you have any stories about this fish or suggestions on how we can make this care guide better, feel free to get in touch and let us know!

You May Also Like