Ranchu Goldfish: Care, Tank Mates & Full Details!

Ranchu goldfish are both peculiar and endearing fish that captivate aquarists worldwide. With their distinct appearance and entertaining behavior, it’s no surprise that they remain one of the most popular goldfish varieties.

Often referred to as the “king of goldfish,” the Ranchu goldfish is a remarkable and elegant species.

As part of the “fancy goldfish” group, Ranchus are selectively bred for their distinct and attractive features. Unlike most fancy goldfish, which originated in China, the Ranchu traces its roots to Japan in the 1600s.

The breed eventually made its way to China and then gained worldwide popularity among collectors and aquarists.

This comprehensive guide will cover everything you need to know about Ranchu goldfish care, including tank size, lifespan, diet, tank setup, and more!

Quick facts About Ranchu Goldfish

Species Name: Carrassius auratus
Family: Minnows and Carps
Care Level: Moderately difficult
Temperature: 65°-77° Fahrenheit
Temperament: Social and peaceful goldfish who will benefit greatly from a compatible tankmate
Color Form: Red, calico, combinations of red and white or gold and white
Lifespan: Approximately 10-15 years
Size: 5”-8”
Diet: Omnivorous, both vegetables and protein are consumed in order to obtain overall health.
Minimum Tank Size: 10 gallons for one full-grown adult Ranchu and an additional 5 gallons per tankmate
Tank Set-Up: Safe and smooth decorations to avoid unnecessary injury but enough to add security within the tank
Compatibility: Suitable with most slow-moving, fancy goldfish, not ideal with other species of fish or fast-moving, slim-bodied goldfish

The Appealing Appearance of Ranchu Goldfish

Ranchu goldfish are renowned for their distinct and charming appearance, making them a popular choice among aquarists.

They possess a round, egg-shaped body that is both stout and compact. The absence of a dorsal fin gives these fish a smooth, arched back that accentuates their unique shape.

Their attractive caudal (tail) fin is short and fan-like, with a slight inward tuck, further adding to their charm.

360 F 406035697 XZELWKEGP16tRvfNurRkz3Af9yEAMEpk

The most distinctive feature of Ranchu’s, however, is the presence of a soft, fleshy growth called a wen, or “helmet,” which covers the top of their head, gills, and cheeks. The wen’s texture is similar to that of a raspberry and can vary in size from one fish to another.

Ranchu’s come in a variety of stunning colors, including gold, white, black, and calico.

Their eye-catching appearance and delightful personality make them a much-loved addition to aquariums worldwide.

Natural Habitat of Ranchu Goldfish

It’s important to note that Ranchu goldfish are not found in the wild. They are a product of selective breeding and belong to the “fancy goldfish” category.

However, their genetic ancestors, the wild carp, inhabit cool streams in Asia. These habitats typically have slow-moving water, ample oxygen, and a neutral pH balance.

When setting up a Ranchu tank, it’s best to replicate the natural habitat of their ancestors.

This includes maintaining cool water temperatures, ensuring adequate oxygenation, and avoiding strong currents that may stress the fish.

Origin and Distribution of Ranchu Goldfish

Ranchu goldfish have an interesting history, with their origins traced back to the 1600s in Japan. Unlike many other fancy goldfish varieties, which predominantly originated in China,

Ranchu’s were selectively bred and developed in Japan. They didn’t make their way to China until a few centuries later, when fishkeeping became more widespread.

Today, Ranchu’s are cherished by collectors and aquarists globally, thanks to their striking appearance and endearing personalities.

They have a particularly strong presence in Asia, where their unique traits and captivating beauty are widely appreciated.

Growth, Size & Lifespan of Ranchu Goldfish

Ranchu goldfish have a considerable range of growth potential, typically reaching a size of 5 to 8 inches in length when fully grown.

However, their growth and size depend largely on the conditions and space available in their habitat. In particularly large tanks or outdoor ponds,

Ranchu goldfish can reach lengths of up to 12 inches or even 18 inches in rare cases.

The lifespan of Ranchu’s is another important consideration for aquarists. With proper care and a suitable environment, they can live anywhere between 8 and 15 years.

Providing a well-maintained tank, a balanced diet, and stable water conditions can significantly improve their chances of reaching a long and healthy life.

ranchu goldfish 2

In summary, Ranchu’s are a fascinating and visually appealing species that make a delightful addition to any aquarium.

Their charming appearance, peaceful demeanor, and captivating history make them a popular choice for fish enthusiasts.

By understanding their natural habitat, origins, growth potential, and lifespan, aquarists can ensure that their Ranchu goldfish enjoy a thriving, healthy life in their care.

Ranchu Goldfish: Behavior and Temperament

Ranchu goldfish are known for their peaceful, friendly temperament, which makes them excellent additions to community tanks.

They are relatively slow swimmers due to their compact body shape and the absence of a dorsal fin, which can make them vulnerable to more aggressive or faster tank mates.

Ranchu goldfish are social creatures and prefer to be in the company of other goldfish, often swimming together in groups.

Tank Setup for Ranchu Goldfish

A well-designed tank setup is crucial for the health and well-being of Ranchu goldfish.

The following sections outline the key components to consider when creating a comfortable and suitable environment for these charming fish.

Tank Size

A minimum of 20 to 30 gallons is recommended for a single Ranchu goldfish, with an additional 10 to 15 gallons per extra goldfish.

This ensures that they have ample swimming space, which is important for their overall health and growth.


When selecting a substrate for a Ranchu goldfish tank, it’s important to choose a smooth, fine-grained material such as sand or small, rounded pebbles.

This helps to protect their delicate undersides from injury while they forage for food at the bottom of the tank.

Decorations and Hiding Spots

Ranchu goldfish appreciate a tank with plenty of decorations and hiding spots, which can provide them with a sense of security.

Live aquatic plants, driftwood, and smooth rocks are all excellent choices. Make sure to avoid any decorations with sharp edges, as these can harm the fish.

Water Parameters

Maintaining stable water parameters is essential for the health of Ranchu goldfish. The ideal temperature range is between 65 and 75°F (18-24°C).

A pH level between 7.0 and 7.5, with a hardness of 4-12 dGH, is recommended. Regular water testing and adjustments should be performed to ensure that the water remains within these parameters.

Filtration and Aeration

Proper filtration and aeration are crucial for Ranchu goldfish, as they help to maintain water quality and oxygen levels.

An external canister filter or a sponge filter is a suitable choice. Additionally, an air pump or an air stone can help to ensure that the water is well-oxygenated.


Moderate lighting is recommended for Ranchu goldfish, as they don’t have specific lighting requirements.

A standard aquarium light on a timer, set for around 8-10 hours per day, should be sufficient to create a comfortable environment and support live plant growth.

Tank Mates

Ranchu goldfish should be kept with other peaceful, slow-swimming fish, as they may struggle to compete for food with faster tank mates like Hillstream Loach, Bristlenose Pleco, Rosy Barbs, etc

Other fancy goldfish varieties, such as Orandas, Ryukins, or Pearlscales, make excellent companions. Avoid keeping Ranchu goldfish with aggressive or fin-nipping fish, as this can lead to stress and injury.


Ranchu goldfish are omnivorous and require a balanced diet of high-quality pellets, flakes, and occasional live or frozen foods, such as brine shrimp or bloodworms.

Feeding them 2-3 times per day, in small quantities that can be consumed within a few minutes, is recommended.


Regular tank maintenance is essential for the health of Ranchu goldfish. This includes weekly water changes of around 25-50% to help maintain water quality, cleaning the filter media, and removing any debris or uneaten food from the tank.

Additionally, it’s important to monitor the water parameters frequently, making necessary adjustments to ensure the health and comfort of your Ranchu goldfish.

In conclusion, Ranchu goldfish are charming and peaceful fish that make excellent additions to a community aquarium.

By providing them with the right tank setup, suitable tank mates, and proper care, you can ensure a healthy, happy environment for your Ranchu goldfish to thrive.

Remember to be attentive to their specific needs, such as water parameters, feeding, and tank maintenance, to ensure their well-being and longevity.

ranchu chinese goldfish 1200x821

Tank Maintenance of Ranchu Goldfish

Proper tank maintenance is essential for keeping your Ranchu goldfish healthy and happy.

By following a regular maintenance schedule and paying attention to the needs of your fish, you can create an ideal environment for them to thrive.

Here are some key aspects of tank maintenance that you should consider:

Regular Water Changes

Performing regular water changes is crucial for maintaining a clean and healthy tank environment for your Ranchu goldfish.

It is recommended to change 10-20% of the water every week to help maintain the water quality and remove any harmful chemicals or toxins that may have built up.

When changing the water, use a water conditioner to neutralize chlorine and other harmful substances commonly found in tap water.

Cleaning the Tank and Decorations

Cleaning the tank and decorations is another important aspect of tank maintenance. Over time, algae and other debris can accumulate on the tank walls, decorations, and other surfaces.

To maintain a clean environment for your Ranchu goldfish, use an aquarium-safe scrubber or scraper to remove any algae from the tank walls.

Clean decorations, rocks, and artificial plants by scrubbing them gently with a soft brush under warm water. Avoid using harsh chemicals or detergents, as these can harm your fish.

Filter Maintenance

Proper filter maintenance is essential for keeping the water clean and ensuring a healthy environment for your Ranchu goldfish.

\Regularly inspect the filter and replace or clean the filter media as needed. Rinse the filter media in tank water, not tap water, to preserve the beneficial bacteria that aid in breaking down waste products.

Replace the filter media according to the manufacturer’s recommendations to ensure optimal filtration.

Monitor Fish Health

Regularly observing your Ranchu goldfish’s behavior and health can help you spot any potential issues early on.

Pay attention to changes in appetite, swimming behavior, or physical appearance, such as the development of spots, lesions, or other abnormal signs. If you notice any signs of illness or distress, consult a veterinarian or experienced aquarist for advice on how to address the issue.

Early detection and intervention can help prevent more severe health problems and ensure the well-being of your Ranchu goldfish.

In summary, proper tank maintenance is vital for the health and happiness of your Ranchu.

By performing regular water changes, cleaning the tank and decorations, maintaining the filter, and monitoring your fish’s health, you can create an optimal environment for them to thrive.

Maintaining a clean and healthy tank will not only enhance the beauty of your aquarium but also promote the longevity and well-being of your Ranchu.

Cute Orange Ranchu Goldfish in the fish tank

Acclimating Ranchu Goldfish

Introducing your Ranchu to their new tank environment is an essential step to ensure their health and well-being.

Proper acclimation helps reduce stress on the fish and minimizes the risk of illness or shock.

Follow these steps for a smooth acclimation process:

  1. Float the bag: When you bring your Ranchu your home, float the sealed bag containing the fish in the tank for about 15-30 minutes. This will allow the water temperature in the bag to slowly equalize with the tank’s water temperature, minimizing temperature-related stress.

  2. Gradually mix tank water: After the temperature has equalized, slowly add small amounts of tank water to the bag over the next 15-20 minutes. This will help the fish adjust to the water chemistry and parameters of their new environment.

  3. Gently release the fish: Using a net, gently transfer the Ranchu from the bag into the tank, avoiding contact with any sharp objects or surfaces that could damage their delicate bodies. Dispose of the water from the bag, as it may contain contaminants.

  4. Monitor the fish: Observe your Ranchu for any signs of stress or atypical behavior during the first few days after introduction. Ensure they are acclimating well to their new environment and interacting well with any tank mates.

Ranchu Goldfish Diet and Feeding

Ranchu goldfish are omnivorous and require a balanced diet to maintain their health and vibrant coloration.

To provide optimal nutrition, consider the following dietary recommendations:

  1. High-quality pellets: Use high-quality sinking pellets specifically formulated for goldfish as the staple of their diet. These pellets contain essential nutrients and vitamins necessary for the fish’s growth and overall health.

  2. Vegetables: Supplement the pellet diet with fresh or blanched vegetables, such as spinach, lettuce, zucchini, or peas. Vegetables provide essential vitamins, minerals, and fiber that aid in digestion.

  3. Live or frozen foods: Occasionally offer live or frozen foods, such as brine shrimp, bloodworms, or daphnia, as treats. These protein-rich foods promote growth and color enhancement.

  4. Feeding frequency: Feed your Ranchu goldfish 2-3 times daily, offering only as much food as they can consume within 2-3 minutes. Avoid overfeeding, as this can lead to water quality issues and health problems.

Ranchu Goldfish Tank Mates

When selecting tank mates for Ranchu goldfish, it’s crucial to choose species that are compatible in terms of temperament, size, and water requirements.

Suitable tank mates for Ranchu goldfish include:

  1. Other fancy goldfish: Other slow-moving, fancy goldfish varieties, such as Orandas, Ryukins, and Pearlscales, make excellent tank mates for Ranchu goldfish. They share similar water requirements, diet, and swimming abilities.

  2. White Cloud Mountain Minnows: These small, peaceful fish can coexist with Ranchu goldfish without competing for food or space. Ensure the tank is large enough to accommodate both species comfortably.

  3. Weather Loaches: Weather loaches are bottom-dwelling fish that can live peacefully with Ranchu goldfish. They have a similar preference for cooler water temperatures and enjoy scavenging for food at the bottom of the tank.

  4. Snails: Snails, such as Nerite or Mystery snails, can also be good tank mates for Ranchu goldfish. They help control algae growth and are unlikely to be bothered by the goldfish.

Avoid adding fast-moving or aggressive fish species, as they can outcompete Ranchu goldfish for food and may cause unnecessary stress.

Additionally, avoid adding species that require significantly different water parameters, as this can be detrimental to the health of both the Ranchu goldfish and their tank mates.

Ranchu Goldfish Breeding

Breeding Ranchu goldfish can be a rewarding experience, as it allows hobbyists to observe the development of new generations and the emergence of unique color patterns and body shapes.

To successfully breed Ranchu goldfish, follow these steps:

  1. Set up a separate breeding tank: Prepare a separate tank with a sponge filter and heater, maintaining water parameters similar to the main tank. The breeding tank should have a volume of at least 20 gallons to provide ample space for the adults and their offspring.

  2. Select healthy, mature fish: Choose a healthy, mature pair of Ranchu goldfish (preferably 1-2 years old) with desirable traits and coloration. Introduce them to the breeding tank and observe their behavior closely.

  3. Increase water temperature: Gradually raise the water temperature in the breeding tank to around 70-74°F (21-23°C) to encourage spawning behavior.

  4. Provide a spawning medium: Place a spawning mop or fine-leaved plants, such as Java moss or Anacharis, in the tank to provide surfaces for the female to lay her adhesive eggs.

  5. Condition the fish: Feed the breeding pair a high-quality diet, including live or frozen foods, to encourage the production of healthy eggs and sperm.

  6. Monitor for spawning: Observe the breeding pair for signs of spawning, which typically occurs in the early morning. The male will chase the female around the tank, nudging her sides until she releases her eggs, which he will then fertilize.

Ranchu Goldfish Fry

  1. Separate adults from eggs: Once spawning is complete, gently remove the adult fish from the breeding tank to prevent them from eating the eggs. The eggs should hatch within 4-7 days.

  2. Care for fry: Once the fry hatch, feed them high-quality, finely ground food, such as baby brine shrimp or commercial fry food, multiple times a day. Perform regular water changes and monitor water parameters to maintain a clean and healthy environment.

As the fry grow, they will develop their unique color patterns and body shapes.

At this stage, it is essential to provide them with adequate space and nutrition to ensure their proper development.

With patience, proper care, and attention to detail, you can successfully breed Ranchu goldfish and enjoy watching the fascinating development of these beautiful and unique aquatic pets.

IMG 2706

Common Ranchu Goldfish Health Issues

Just like any other fish species, Ranchu goldfish can be susceptible to various health issues.

Providing them with optimal care, a well-maintained environment, and a balanced diet is essential in minimizing the risk of health problems. Some of the common health issues

Ranchu goldfish may encounter include:

  1. Swim Bladder Disorder: Swim Bladder Disorder displays abnormal swimming behavior in Ranchu goldfish, such as floating upside down or swimming sideways. Overfeeding, constipation, or gulping air at the water surface often cause it. To treat swim bladder disorder, ensure you feed your Ranchu goldfish easily digestible, high-quality food and avoid overfeeding.

  2. Fin Rot: Fin rot is a bacterial infection that causes the fins to appear ragged and discolored. It can be caused by poor water quality or injury to the fins. To prevent fin rot, maintain good water quality, perform regular water changes, and provide a stress-free environment.

  3. Ich: Ich, also known as white spot disease, is a parasitic infection that causes small, white spots on the fish’s body and fins. To treat Ich, increase the water temperature to 86°F (30°C) for a few days and use a commercial Ich treatment as directed.

  4. Fungal Infections: Fungal infections often present as cotton-like growths on the fish’s body, fins, or mouth. These infections are usually caused by poor water quality or injuries. To prevent fungal infections, maintain optimal water parameters, and provide a clean environment for your fish.

  5. Dropsy: Dropsy is a condition characterized by a swollen, bloated appearance, and raised scales. It is typically caused by bacterial infections or kidney failure. Dropsy can be challenging to treat, and early diagnosis is crucial. Consult a veterinarian for appropriate treatment options.

Regular water changes, a balanced diet, and proper tank maintenance are essential in preventing health issues and ensuring the longevity of your Ranchu.

Signs of Stress in Ranchu Goldfish

Identifying signs of stress in Ranchu goldfish is essential to ensure their well-being.

Recognizing these signs early can help you address potential issues and maintain a healthy environment.

Common stress indicators in Ranchu’s include:

  1. Clamped fins: When a Ranchu goldfish is stressed, it may hold its fins close to its body instead of spreading them out.

  2. Gasping at the surface: If a Ranchu is seen gasping for air at the water surface, it may be a sign of poor water quality or insufficient oxygen levels.

  3. Loss of appetite: A stressed Ranchu may lose interest in food or refuse to eat altogether.

  4. Erratic swimming: Stressed goldfish may display abnormal swimming patterns or erratic behavior.

  5. Changes in color: In some cases, stress can cause a Ranchu goldfish to lose its vibrant coloration or develop a pale appearance.

Additional Tips for a Healthy Aquarium

To maintain a healthy aquarium for your Ranchu goldfish, consider these additional tips:

  1. Acclimate your fish: When introducing new fish to your aquarium, make sure to acclimate them properly to avoid stress and potential health issues.

  2. Quarantine new fish: Before adding new fish to your main tank, place them in a separate quarantine tank to observe their health and ensure they do not introduce diseases.

  3. Test water regularly: Regularly test water parameters, including ammonia, nitrite, nitrate, pH, and temperature, to maintain a stable environment.

  4. Avoid overcrowding: Overcrowding your aquarium can lead to stress and poor water quality, so ensure you provide enough space for each fish.

Should You Get a Ranchu Goldfish for Your Aquarium?

You can make a Ranchu goldfish a wonderful addition to your aquarium if you meet their specific care requirements.

They are beautiful, unique fish with engaging personalities that can bring joy to aquarists. However, they do require more care and attention than some other fish species.

If you’re willing to invest the time and effort in providing a suitable environment and maintaining their health, a Ranchu goldfish can be a delightful addition to your aquatic family.

360 F 406035697 XZELWKEGP16tRvfNurRkz3Af9yEAMEpk

Conservation Status of Ranchu Goldfish

Since people have selectively bred Ranchu goldfish as an ornamental species, they don’t exist in the wild, so they don’t have a conservation status.

Consequently, you don’t need to worry about their survival or population levels.

However, responsible fishkeeping practices are essential to protect wild fish populations and habitats from potential harm due to the release of non-native species or their diseases.

Always take care to never release any aquarium fish into the wild.

Availability & Pricing

Ranchu’s are widely available in most pet stores and from online retailers specializing in ornamental fish.

The price of a Ranchu goldfish can vary significantly depending on factors such as size, color, and quality. Common varieties may cost between $10 to $30, while high-quality or show-grade specimens can fetch prices ranging from $50 to several hundred dollars.

It’s essential to purchase your Ranchu goldfish from reputable sellers to ensure you receive a healthy, high-quality fish.

Frequently Asked Questions About Ranchu Goldfish

1. How can I tell the difference between a Ranchu goldfish and a Lionhead goldfish?

The most noticeable difference between Ranchu and Lionhead goldfish is the dorsal fin.

Ranchu goldfish do not have a dorsal fin, while Lionhead goldfish have one.

Additionally, Ranchu goldfish have a more rounded back and a shorter, more compact body compared to Lionhead goldfish.

2. Are Ranchu goldfish difficult to care for?

Caring for Ranchu goldfish poses a moderate challenge because they require specific water parameters, are susceptible to water quality issues, and need a proper diet.

However, with proper care and attention, aquarists can successfully maintain Ranchu goldfish in a healthy aquarium environment.

3. Can Ranchu goldfish live with other types of goldfish?

Yes, Ranchu goldfish can coexist with other goldfish varieties, such as Orandas, Fantails, and Lionheads.

It is essential to ensure all fish in the aquarium have similar care requirements and that the tank is large enough to accommodate them.


If you prepare to meet their specific care needs, you can add the unique and beautiful variety of Ranchu as a delightful addition to your aquarium.

By providing a suitable tank environment, maintaining water quality, and offering a balanced diet, you can enjoy the company of these charming fish for years to come.

Remember to purchase your Ranchu from reputable sellers and educate yourself on their care requirements to ensure a healthy and thriving aquatic environment.