Our Full Guide to Caring for Ryukin Goldfish

Alison Page

Alison Page


ryukin goldfish

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Ryukin goldfish are an unusual variety of fancy goldfish from Japan. These gorgeous fish are beginner-friendly and can live in an indoor fish tank or outside in your garden pond.

To learn more about the origins of these delightful, egg-shaped goldfish, including how to care for and breed them, keep reading!

Ryukin Goldfish – At A Glance

Ryukin Goldfish Info
Scientific Name:Carassius auratus auratus
Common Name (species)Ryukin goldfish
Care LevelModerate
ActivityQuite active but tend to be clumsy swimmers
Lifespan10 years on average
Tank LevelAll areas of the water column
Minimum Tank Size20 gallons
Temperature Range65o to 72o F
Water Hardness5 to 19 dGH
pH RangeBetween 6.0 and 8.0
Filtration/Flow RateSlow flow rate but needs excellent filtration
Water typeFreshwater
CompatibilityPeaceful, but avoid keeping very small fish and shrimp
Plant-safe?Partly. Tends to dig up plants and eat tender leaves.

Origins of the Ryukin Goldfish

Ryukins are egg-shaped fancy goldfish with a characteristically high back or “dorsal hump” and short stubby bodies. The tail fins are split or double, and Ryukins also come in a long-tailed variety called a Fringe-tail or Ribbon-tail.


Ryukin goldfish have a life expectancy of between ten and 15 years. They can live longer when given a high-quality diet and optimal living conditions.


Ryukin goldfish typically grow to measure approximately 6 inches long. However, these impressive fish can reach a huge 10 inches in some exceptional cases.

Colors and Patterns

Ryukin goldfish come in many different color morphs and patterns, including the following:

  • Red
  • Red and white
  • Tri-color
  • Calico
  • White
  • Chocolate

This variety of goldfish usually has nacreous or metallic scales.

Availability and Price

Ryukin goldfish are readily available in your local high-street fish store and online.

When it comes to price, the Ryukin is typically more expensive to buy than more common fancy goldfish varieties, fetching around $10 per fish. The red and white color morph is the most common variety of these beautiful fish and also the cheapest.

However, if you want a more unusual color or a long-tail specimen, you’ll pay more, as these fish are pretty rare and usually only available from online breeders.

Ease of Care

Ryukins are quite hardy compared to other fancy goldfish types and can live in a large fish tank or a well-maintained garden pond, provided that the environment is suitable and their companions don’t outcompete the slow-swimming Ryukins for food.

Ryukin Goldfish Care Guide

ryukin goldfish

In this part of our guide, you’ll learn everything you need to know about caring for the Ryukin goldfish.

Tank Size

Contrary to popular belief, goldfish will keep growing regardless of the size of the container in which they’re kept. If your aquarium is too small, developmental problems and stunted growth will affect your fish, causing a failure to thrive and shortening their lifespan.

Ryukins, like most goldfish, grow quickly during their first couple of years, so we recommend starting off with the largest tank you can reasonably fit into your space. That way, you won’t need to upsize in the future.

We recommend starting with a 20-gallon aquarium as a minimum, although larger is better. Goldfish must always be kept in groups to prevent stress, and if you want to keep more fish, you must add an additional 10 gallons for each one.

Tank Shape

Like all round-bodied goldfish, Ryukins are clumsy, slow swimmers, and long-tailed varieties do not cope well in a deep tank. Therefore, a long, shallow aquarium is preferred.

Goldfish need a well-oxygenated environment to thrive, so the tank must offer plenty of surface area for good gaseous exchange.

Although fully grown fancy goldfish do not jump, juveniles are more agile, and I have seen one leap right out of the water when startled. For that reason, you should choose a tank with a well-fitting lid or cover slide to prevent accidents.

In addition, if the water is covered it doesn’t evaporate as quickly, and you won’t need to worry about dust and foreign bodies settling on the water and polluting the tank.

Do not keep goldfish in a goldfish bowl!

Traditional goldfish bowls are far too small for Ryukins and other goldfish, and they don’t provide enough surface area for efficient gaseous exchange.

Can Ryukin Goldfish Live Together?

As previously mentioned, goldfish of all varieties must be kept in groups.

Overcrowding causes stress, and your fish are more likely to be injured during feeding frenzies. Therefore, you must provide your fish with plenty of swimming space and be careful not to overstock your tank or pond.

As a general rule, you must allow 1 inch of fish per 1 gallon of water in your aquarium or pond.

Water Parameters

Ryukin goldfish can live in cold water, ideally with a temperature of between 65o and 72o F. However, they can also do well when kept outside in a pond, even if the temperature drops to a couple of degrees below freezing in winter.

The water pH should be between 6.0 and 8.0, with a water hardness of 5 to 19 dGH.

Ammonia and nitrite levels must always be zero, and nitrates should ideally be below 20 ppm.


All varieties of goldfish are filthy animals that produce vast amounts of waste daily. So, to cope with that mess, you need a highly efficient, powerful filtration system that circulates the entire volume of tank water through the filter media at least four times per hour.

Unfortunately, a powerful filtration unit will generate strong water flow through the tank, which does not suit the feeble swimming ability of the Ryukin goldfish.

To prevent the fish from being buffeted and stressed, you should use plants or decorations to buffer the current or choose a filter unit with an adjustable outflow fitting that can be directed away from your fish.

Tank Maintenance

To keep your goldfish tank clean and safe for your Ryukins, you must change 30% of the water every week to remove nitrates.

I recommend using an aquarium vacuum cleaner every week to suck out leftover food, organic debris, and dead plant matter from the substrate and underneath decorations that would otherwise rot and pollute the water.

Trim dead leaves and broken stems off living plants to keep them tidy and prevent overgrowth, and use an algae scraper to get rid of unsightly patches of algae on the aquarium glass.

However, since Ryukin goldfish eat algae as part of their diet, you might want to leave a small area of green algae for the fish to graze on between meals.


You can use any form of decoration that you like in a goldfish tank.

However, Ryukins are poor swimmers, so we recommend avoiding sharp, rough objects that could injure your fish, which is especially important if you have long-tailed varieties.

So, choose driftwood, smooth stones, and pebbles, and steer clear of twisted roots and resin decorations with rough surfaces.

The best substrate to choose is smooth, large-gauge gravel, as it won’t harm the goldfish when they’re foraging through it.

Are Ryukins Plant-Safe?

Like all goldfish varieties, Ryukins love to dig around in the substrate and around plant bases, foraging for scraps of food. That can disturb the plant’s roots, preventing them from thriving and even uprooting them altogether. Goldfish also enjoy nibbling on tender new shoots and fragile plant leaves, which can cause a lot of damage.

You can prevent damage to your plants by growing them in clay pots or choosing varieties that will grow when attached to pieces of wood, rock, or decorations with fine thread or fishing lines.

As an alternative, you could use silk plants instead, which look lovely and won’t get damaged. Don’t use plastic plants! Some plastic plants are hard and have sharp edges or points that can do a lot of damage to your goldfish and are best avoided.


Fish do not need bright light in their environment and can do fine with standard LED aquarium lighting.

However, all your livestock needs a clear day and night cycle so that they know when to become active, when to feed, and when to rest. In addition, if you keep live plants, they will need a minimum of eight hours of light every day for photosynthesis.

Nutrition and Feeding

Ryukins are omnivorous fish that eat a combination of plant matter, meaty protein, and certain species of algae.

I feed my Ryukins a balanced diet of fancy goldfish pellets, frozen meaty foods, and blanched vegetables as an occasional treat.

It’s essential to include some meaty food in your goldfish’s diet because round-bodied fish are highly susceptible to digestive disorders, including constipation, which can affect the correct function of the fish’s swim bladder.

Swim bladder disorders prevent the fish from swimming on an even keel, causing stress and potentially leading to disease. Feeding your fish fresh veggies and meaty foods daily helps to keep their digestive tract functioning correctly.

Live Foods

If you keep your goldfish in a garden pond, they will eat whatever worms, insects, small crustaceans, and insect larvae that they can find in their environment.

However, although you can buy live food from your local pet store, I don’t recommend feeding that to your fish. These foods regularly arrive containing bacteria and parasites that could harm or kill your Ryukins and are best avoided.

Similarly, I don’t recommend harvesting live food from the natural environment because that can be contaminated with chemicals and bacteria.

How Much to Feed Ryukin Goldfish

ryukin goldfish

You should feed your Ryukins two to three small meals every day, offering only what the fish will clear in a couple of minutes to prevent overfeeding.

Tank Mates

Goldfish should be kept in groups, ideally of their own kind, to prevent stress. You can combine a mixture of different varieties of Fancy goldfish in a large tank or pond with no issues. However, it’s not advisable to keep them with slim-bodied types.

The slim-bodied goldfish varieties are fast, agile swimmers that tend to bump and barge the slower Ryukins, leading to stress and injuries.

You can also keep large shrimp varieties and snails with Ryukins. However, it’s best to avoid very small fish species and inverts as the large goldfish will almost certainly view them as a food source.

Health and Diseases

Ryukin goldfish are pretty hardy and will do well if you provide them with the correct diet and living conditions.

That said, there are a few common fish diseases that can affect goldfish, including:

  • White Spot Disease (Ich)
  • Bacterial infections
  • Flukes, including fish lice, anchor worms, and skin flukes
  • Swim bladder problems

Keep disease out of your main tank by placing all new arrivals in a separate quarantine set up for at least two weeks before adding them to your collection. That allows you to spot any health issues and treat them without risking infecting your main tank.


Ryukins breed readily in your tank and especially in a pond setting. In fact, a friend of mine has a goldfish pond in her backyard and regularly finds a few baby fish appearing in the summer months.

It’s pretty much impossible to tell males from females until the fish are mature and come into spawning condition.

When ready to spawn, females tend to be fatter than males, which develop a rash of tiny white tubercles on their gill covers. Therefore, it’s best to buy a small group of fish so that you’re sure to get a mix of both sexes.

Spawning Tank

If your fish are tank-kept, you need to set up a dedicated 20-gallon breeding tank so that the fish have plenty of space.

For the few weeks prior to spawning, feed your fish plenty of high-protein meaty foods to bring them into breeding condition. Some breeders find that keeping the sexes separate during that time makes spawning more likely when the Ryukins are put together.

You can replicate the goldfish’s preferred outdoor spring and summer spawning conditions by raising the water temperature by a few degrees per day until the temperature is between 68o and 74o F.

Decorate the breeding tank with clumps of fresh plants or spawning mops and flat rocks where the female Ryukins can lay their eggs.

Keep the breeding tank scrupulously clean by changing 20% of the water daily until spawning commences.


Following several hours of courtship, the female Ryukin lays up to 10,000 eggs, which are fertilized by the male.

Once the eggs have been fertilized, you must remove the parents from the spawning tank; otherwise, they will eat the eggs and fry.

The fry usually hatches after about a week and is immediately free-swimming, and you can feed them spirulina, finally crushed goldfish flakes, and live baby brine shrimp.

Once the baby fish are an inch or so long, you can add them to your main tank to join the adults. As juveniles, goldfish are a bronze or drab brown color and don’t show their adult coloration until they reach around two months of age.

Final Thoughts

Ryukin goldfish are a beautiful and unusual variety of these perennially popular pets. You can keep Ryukins in your garden pond or in a large fish tank, ideally in groups of their own kind or with other fancy goldfish varieties.

Provided you feed these omnivorous fish a variety of high-quality foods, including a daily portion of meaty protein, and keep them in a well-maintained, spacious habitat, you can expect to enjoy your fish for at least 10 years.

Do you keep Fancy goldfish? What varieties do you have, and do they live in a pond or tank? tell us about your fish in the comment box below.

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