Ryukin Goldfish: Care, Diet, Tank Setup, & More!

Ryukin Goldfish Isolated in Blue Background
Featured Image – Ryukin Goldfish
Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: June 12, 2024
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The standard goldfish is highly cherished by aquarium aficionados. Nonetheless, many are in search of a fish that not only enjoys the longevity of a goldfish but also boasts a more captivating appearance. Enter the Ryukin goldfish – a lively, beautifully designed species merging vivid colors and a split tail with timeless charm. This guide aims to provide you with all the essential information to introduce this modern take on a classic into your home aquarium.

Article Summary

  • Ryukin Goldfish is egg-shaped with a large dorsal hump, a split or double caudal fin, and can have three or four lobes on the caudal fin.
  • They are omnivores and should be fed a balanced diet of commercial foods, vegetables, and protein sources.
  • A minimum tank size of 30 gallons is recommended for one Ryukin Goldfish.

Species Overview

Common namesRyukin goldfish
Scientific nameCarassius auratus
SpeciesC. auratus
Size6-8 inches
Lifespan10-15 years
DistributionWorldwide in captivity
ColorOrange, red, black, white, silver, blue, calico
Minimum tank size30 gallons
Place in the tankMiddle/top

History and Background

The Prussian carp went from being farmed for food, to having one of the most popular descendents in the world, read on to find out more.


Like all goldfish, the ryukin goldfish is a fancy goldfish mutation hailing from the Prussian carp. More specifically, the ryukin goldfish is likely a mutation of the Wakin goldfish. It is named “Ryukin” because it supposedly reached Japan from China when it was transported through the Ryukyu islands.

Is Ryukin goldfish rare?

The long-tailed variation of the ryukin goldfish is rare and generally much more expensive. However, the short tailed ryukin goldfish can often be found in local pet stores.

Where did the first ryukin goldfish come from?

The ryukin goldfish, like other fancy goldfish originally hailed from the common goldfish and were specifically bred for specific characteristics such as longer fins, and egg shaped body, or various colorations (blue, black, chocolate, white).

While the first ryukin goldfish was bred in China, it was brought to Japan in the late 18th century where it was named for the Japanese islands of Ryukyu which are now referred to as the Okinawa Prefecture.

Are Ryukin goldfish fast?

No, compared to other freshwater fish the ryukin goldfish is quite slow. However, they are considerably faster than other fancy goldfish. This makes them a bit hard to find companions for as they will bully other fancy goldfish with their speed, but get bullied by other fish that are faster than them like the comet goldfish. We’ll discuss this more in the tankmates section.

What is the difference between a fantail and a Ryukin goldfish?

The fantail goldfish is one of the many fancy goldfish varieties that has a split caudal fin, or double tail. The ryukin is a specific variation of the fantail goldfish that has three or four tail lobes and its fin can be double the length of its body. In other words, all ryukin goldfish are fantails, but not all fantails are ryukins.


Ryukin Goldfish In A Planted Aquarium
Ryukin Goldfish In A Planted Aquarium

With it’s bold, striking colors and startling tail, this fish is one you’ll remember.

What do ryukin goldfish look like

The ryukin is an egg shaped fancy goldfish that has a large dorsal hump on top of the body. Additionally they have a split or double caudal fin and can have three, or even four lobes on the caudal fin. They come in a wide variety of colors including orange, red, black, chocolate, and calico. They are commonly found with orange, white, and black coloring as well making them one of the most sought after and beautiful fish.

How to tell the gender of a ryukin goldfish

The ryukin goldfish is one of the few goldfish you can accurately identify males and females just by looking at them. When observing the underside of ryukin’s you’ll notice that the anal fin is much closer to the tail fin in males compared to females. Additionally, while they are both egg shaped goldfish male’s have a smaller and skinnier body than females.


The two main varieties of ryukin are short and long finned. The short finned variety has a tail that is less than half the length of their body, whereas the long finned variety has a tail fin that is over half the length of their body.

Here are some tips on how to choose a quality Ryukin goldfish…

How to choose your goldfish? Selecting High quality Ryukin

How big does a ryukin goldfish get

Average ryukin goldfish size ranges from six to eight inches which falls in the middling size range when compared to other goldfish species.

How fast do ryukin goldfish grow

Baby fish should grow to roughly 2 inches in the first 6 months, and 3 inches in the first year under ideal conditions. After the first year your goldfish should grow about 1 inch per year until reaching the maximum size range (6-8 inches).

Temperament and Tankmates

Close-up Image of an Orange White Ryukin
(1) Close-up Image of a Short Tail Orange and White Ryukin with Black Specks

These fish have an excellent temperament and get along with most other fish providing that there is enough room in your aquarium.

Can 2 ryukin goldfish live together?

Ryukin are peaceful fish and can be kept together or with other fish species.

How many ryukin goldfish should be kept together?

There is no limit on how many ryukin’s you keep together as long as you have a large enough goldfish aquarium. All goldfish species put a heavy bioload on a fish tank, meaning to keep multiple in the same tank you need an excellent filtration system to keep pristine water quality.

How many ryukin goldfish in a 10 gallon tank

You should not keep an adult ryukin in a ten gallon tank for any extended period of time. Not only is there not enough space for them, which will cause a very stressed fish, they can also overwhelm the fish tank system. The only times you can keep this fish species in a 10 gallon tank is when they are first born, or if you are very briefly putting them in there to perform tank maintenance.

What fish can live with ryukin goldfish

Suitable tank mates for ryukin are ones that are of similar size and speed. Most goldfish of the fancy variety will do well as they have similar living needs, and won’t be mistaken for food like smaller fish will. However, some freshwater fish species can also be suitable aquarium companions, just be sure to do your research before adding them to your fish tank.

Top 5 Compatible tank mates

  1. Zebra danios-a common aquarium fish that does well with ryukin despite its small size. They should be kept in large schools which will help to deter any nippy goldfish. When kept with fancy goldfish such as the ryukin their speed will keep them from becoming a snack.
  2. Corydoras catfishCorydoras are peaceful fish that occupy the bottom of the tank meaning that they won’t have much interaction with your ryukin.
  3. Fantail goldfish– Like mentioned earlier this double finned fish is very similar to the ryukin and will do excellent as a companion as long as you have enough space to house the two.
  4. Oranda goldfish-another in the goldfish family, the oranda is a slow moving and large species that can provide excellent companionship in a freshwater aquarium or outdoor pond space.
  5. Lionhead goldfish-this fancy goldfish will do well with a ryukin and won’t be able to be bullied by it.

Bad Tank Mates

You shouldn’t house any tropical fish with your ryukin as they prefer cold water and having tropical species will require them to be at the edge of their comfortable range. Additionally, you shouldn’t keep weaker fish such as the bubble eye or celestial eye goldfish with ryukins. While the same species usually makes good tank mates ryukin goldfish tend to be aggressive and bump into these more sensitive fish.

Tank Requirements

A Fish Tank with Goldfish
A Fish Tank with Goldfish

One of the easier goldfish varieties to manage due to its simple tank requirements.

Tank Size

Due to their large size and being notable for being messy you should keep your ryukin in no less than a 30 gallon aquarium for one fish. There are no specific requirements for tank shape, so you can use an elongated or tall tank. However, be aware that these gorgeous fish have long tails and a hard time turning so your goldfish aquarium size should accommodate that.

How many ryukin goldfish can you keep?

The amount of goldfish that you keep depends on the size of your enclosure. Fish keepers with outdoor ponds will likely be able to keep more of this species than those with an indoor fish tank as there’s more room for them to take care of the ryukin goldfish’s needs.

How many gallons does a Ryukin need?

You should alot 30 gallons for the first ryukin, and an additional 15 gallons for each additional goldfish.

Water Parameters

Tank Size>30 gallons
Water TypeFreshwater
Water Temperature65-72
Water pH6.0-8.0
Water Hardness5-19 dGH

Tank setup:

What substrate should I use?

We recommend using a medium sized gravel substrate that is large enough to not be intentionally swallowed, but small enough that if accidentally eaten it can easily pass through bowels. Goldfish are opportunistic eaters and will chow down on anything they think might be food, this is particularly bad for large gravel pieces as they can get stuck and cause infections and even need surgeries to remove.

Do I need a filter?

Yes, regardless of the species you are keeping you should have an appropriately size filtration system for the tank. We recommend a filter that has four times the outflow power of your tank size. For a 30 gallon tank you need a filter that is rated for at least 120 gallons per hour.

Should I get a pump?

A pump is helpful to provide circulation and oxygen to all parts of the tank. In an aquarium where there are live plants it is especially helpful to have a pump to make sure bottom dwelling fish are getting enough oxygen circulation.

Do I need a water heater?

For the ryukin goldfish you likely will not need a water heater because it is a cold water species. However, if you are keeping them in outdoor enclosures and are located in a very cold climate area your goldfish might need a heater if the temperature drops below 65 degrees Fahrenheit.

What temperature do ryukin goldfish need?

Ryukin goldfish are a cold water fish and prefer the water temperature to be between 65 and 72 degrees Farhenheit.

What kind of lighting should I get?

Goldfish are not particularly picky when it comes to lighting requirements, any aquarium light will do. We do suggest adding light to your goldfish tank especially if it’s a poorly lit area, otherwise, your goldfish might lose color.


If you are planning to add plants to your tank you can tailor the light to their needs and trust that the ryukin goldfish are pretty hardy creatures when it comes to lighting.

Can I add plants to my tank?

Yes, adding live plants or artificial plants to your tank will compliment the colors of your beautiful ryukin goldfish as well as providing it with plenty of spaces to play and hide in. Live aquatic plants that are easy to keep include hornwort and java moss.

If you’re looking to use artificial plants be sure to purchase soft silk plants. Silk plants won’t injure your goldfish if they swim too close to them, unlike other fake plants that have sharp edges.

Diet and Health

A girl feeding a goldfish
A girl feeding a goldfish

Like all goldfish, ryukin are messy eaters which can cause problems for their diet and health. Read on to find out more on how to ensure these fish have the nutrition they need.

What do ryukin goldfish eat

Like most goldfish, ryukin goldfish are omnivores and will eat almost anything you offer them. A balanced diet includes a mixture of plant matter, vegetables, and protein sources.

What to feed ryukin goldfish?

You should feed your ryukin goldfish a diet consisting of 80% commercially available foods such as high quality dry flakes, and 20% supplemental nutrition in the form of vegetables and protein like brine shrimp and anchor worms.

When choosing frozen foods and other nutrition try to find ones specifically targeted towards goldfish…

If you’re not a fan of live foods, brine shrimp, fish blood worms, and other meaty substances come as frozen foods and will still make for a balanced diet. When choosing frozen foods and other nutrition try to find ones specifically targeted towards goldfish as they have the necessary vitamin and mineral supplements for your fish to remain healthy.

How often to feed ryukin goldfish

Aim to feed your goldfish once to twice a day. These fish are prone to overeating and part of ryukin goldfish care is managing the amount of food given to prevent overeating and other common problems such as constipation, bloating, and swim bladder problems.

How much do you feed ryukin goldfish?

Feed your goldfish according to the three minute rule to ensure that they are receiving enough nutrition but also not overeating. To follow the three minute rule follow the steps below;

  1. Drop 3 to 4 food morsels into the tank, start a timer
  2. Allow your fish to eat the food at their own rate, only adding more when all food has been eaten
  3. Continue this pattern until 3 minutes is over

It is important to note that at the end of the three minutes you shouldn’t just leave uneaten food in your aquarium for your fish to snack on later. Leftover food can lead to the fouling of your water and detrimental water parameters.

Common diseases of ryukin goldfish?

Ryukin Goldfish Looking At Its Own Reflection
Ryukin Goldfish Looking At Its Own Reflection

To keep your fish healthy you should perform regular tank maintenance and feed a high quality diet. However, diseases are often present in aquariums regardless of the standard of ryukin goldfish care.

Swim bladder disorders

Swim bladder problems are particularly common in goldfish due to the passage between their esophagus and swim bladder being open. This means if they gulp down too much air while eating floating flakes they could potentially end up swimming upside down.

Other symptoms include swimming sideways, lethargy, and loss of appetite. Treatment includes using a sinking food diet, water changes, and feeding the fish shelled peas. In severe cases it is necessary for a vet to use a needle to remove excess air from the bladder.

Bacterial infections

Due to their messiness, goldfish are often susceptible to bacterial infections, especially if the tank environment is not maintained. Depending on the specific infection you might need gram negative or positive broad spectrum antibiotics, these are generally over the counter medications and can easily be found at pet stores.

Fish Lice

A parasitic infection that can spread rapidly if not identified and treated immediately. This parasite looks like small specks on the host and can be seen moving around on the host or in the water.

Symptoms of fish lice include paleness, itching, secondary infections, excessive mucus, and lethargy. Fish lice treatment can include manually removing them, or dosing the environment with diflubenzuron, cyromazine, and potassium permanganate (though it won’t kill lice eggs).

How long do ryukin goldfish live

These fish can live up to 10 to 15 years in ideal tank conditions.


A Pair of Ryukin Goldfish Swimming Near Aquarium Substrate
(2) Ryukin Pair

Like many other goldfish, ryukin’s are easily captive-bred making them inexpensive and easy to find.

Can you breed a ryukin goldfish?

As ryukin’s are very social fish it is extremely easy to breed them and many owner’s do it by accident.

How to breed a ryukin goldfish?

Begin a few weeks before you plan to breed your fish and set up a separate breeding tank. The breeding tank should have leafy plants to create natural spawning mops, or you can buy artificial ones. Females and males should be separated and fed a high protein diet the weeks prior to the mating process.

Once your breeding tank is cycled and you are ready to begin, add the mating pair to the tank and slowly drop the water temperature to 60 degrees Fahrenheit. Gradually increase the temperature by 2 to 3 degrees each day while continuing to feed a high protein diet until the goldfish spawn.

When they have mated your notice the female’s abdomen swells up from carrying eggs, she can lay upwards of 10,000 at once.

Once the eggs have been laid immediately place the adults in a separate tank or they will begin to eat the young.

Ryukin goldfish eggs hatch in four to seven days and will become free swimming a few days after that. Once they are free swimming you can begin feeding them fry food or infusoria until they are large enough to eat baby brine shrimp (about 2 weeks after hatching).

Is the ryukin goldfish for you?

If you’re looking for a twist on the classic goldfish, the ryukin could be for you. With its peaceful nature, hardy attitude, and appealing appearance it brings everything you could want to your tank.


In conclusion, whether you are a novice or an experienced goldfish keeper, if you have enough room in your tank, the ryukin goldfish can be an excellent addition that can add much personality to your aquarium.

(1) Lawrencekhoo, CC BY-SA 4.0, via Wikimedia Commons
(2) Lawrencekhoo, CC BY-SA 4.0, via Wikimedia Commons

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