Ranchu Goldfish Care: Tank Setup, Diet, Tank Mates, Diseases & More!

If you’re considering getting a ranchu goldfish, it’s important to know everything you need to give them the best care possible. Ranchu goldfish are a popular variety of goldfish known for their unique appearance, round body shape, and distinctive headgrowth. However, they require specific care to thrive in your aquarium.

Ranchu Goldfish require a tank size of at least 20 gallons per fish, pH levels between 6.5-7.5, and a temperature range of 65-72°F. They are omnivores and need a varied diet of high-quality pellets or flakes, vegetables, and occasional live or frozen foods. Regular water changes and tank maintenance are also important for their health.

Additionally, ranchu goldfish need a balanced diet that includes high-quality pellets, vegetables, and occasional treats like bloodworms.

Overfeeding can lead to health problems, so make sure to feed them small amounts several times a day. With proper care and attention, your ranchu goldfish can live a long and healthy life.

ranchu goldfish

Species Summary

Are you thinking about getting a ranchu goldfish? Before you do, it’s important to understand the basics of their care.

In this section, we’ll cover everything you need to know about ranchu goldfish, including their origin, lifespan, appearance, size, growth rate, behavior, and temperament, as well as the differences between males and females.


Ranchu goldfish originated in Japan, where they were first bred in the late 1800s. They were created by crossbreeding lionhead goldfish and other fancy goldfish varieties.


Ranchu goldfish have a relatively long lifespan compared to other types of goldfish, typically living for 10-15 years with proper care. However, some ranchu goldfish have been known to live for over 20 years!


Ranchu goldfish are easily recognizable by their round, chubby bodies and distinctive head growth, known as a wen.

Their wen can come in a variety of shapes and sizes, ranging from small bumps to large, flowing head growths that cover their entire face. They also have a double tail, which gives them a unique swimming style.


Ranchu goldfish are a small to medium-sized goldfish, typically growing to be around 6-8 inches long. However, some ranchu goldfish can grow to be larger or smaller depending on their genetics and environment.

Growth Rate

The growth rate of ranchu goldfish can vary depending on a number of factors, including water quality, temperature, and diet.

However, on average, ranchu goldfish will grow to be around 2-3 inches in their first year of life, and then continue to grow slowly over the next several years.

Behavior & Temperament

Ranchu goldfish are generally peaceful and social fish, and can be kept in groups with other goldfish species.

They are also known for their playful and curious personalities, and will often interact with their owners.

However, they can be sensitive to water quality and temperature changes, so it’s important to keep their environment stable and well-maintained.

Male vs Female

It can be difficult to tell the difference between male and female ranchu goldfish, as they have similar physical characteristics.

However, male ranchu goldfish may develop breeding tubercles on their gill covers and pectoral fins during the breeding season, while female ranchu goldfish may have a slightly rounder body shape.

Overall, ranchu goldfish are a unique and fascinating species that can make great pets for experienced fish keepers.

By understanding their care requirements and providing them with a stable and healthy environment, you can help ensure that your ranchu goldfish lives a long and happy life.

Tank Setup

Setting up a proper tank for your ranchu goldfish is crucial for their health and well-being. Here are some important factors to consider:

Tank Size

The size of your tank will depend on how many ranchu goldfish you plan to keep.

It’s recommended to have at least 20 gallons of water per fish. Keep in mind that ranchu goldfish are active swimmers and require ample space to move around.


Lighting is important for the overall health of your ranchu goldfish. They need a regular day and night cycle to maintain their biological rhythms. A timer can be useful to ensure consistent lighting.

Filtration & Aeration

Filtration and aeration are essential for maintaining a healthy environment for your ranchu goldfish.

A good filter will remove waste and debris from the water, while aeration will provide oxygen for your fish to breathe. Make sure to choose a filter and air pump that are appropriate for the size of your tank.


Ranchu goldfish are coldwater fish and prefer temperatures between 65 and 72 degrees Fahrenheit. A heater may be necessary to maintain a consistent temperature in your tank, especially during colder months.


Choose a substrate that is appropriate for your ranchu goldfish. Sand or smooth gravel is recommended, as rough or sharp substrates can damage their delicate fins and scales. Make sure to thoroughly rinse the substrate before adding it to the tank.


Adding decorations to your tank can provide a stimulating environment for your ranchu goldfish.

However, be careful not to overcrowd the tank with too many decorations, as this can limit swimming space and increase the risk of injury.


Live plants can help maintain a healthy environment for your ranchu goldfish by providing oxygen and removing waste from the water.

However, make sure to choose plants that are compatible with your fish and won’t be eaten or uprooted.

With these factors in mind, you can create a comfortable and healthy environment for your ranchu goldfish to thrive in.

Personally, I have found that my ranchu goldfish are happiest when they have plenty of space to swim around and explore.

I also like to add a few live plants to their tank, as they seem to enjoy nibbling on the leaves and hiding among the foliage.

Water Quality

Keeping the water in your ranchu goldfish tank clean and healthy is crucial for the health and wellbeing of your fish. In this section, we will cover the key aspects of water quality that you need to know to ensure your fish stay healthy and happy.

Water Temperature

The ideal water temperature for ranchu goldfish is between 68-74°F (20-23°C). You can use a thermometer to monitor the temperature and adjust it as necessary.

Avoid sudden changes in temperature, as this can stress your fish and make them more susceptible to illness.

Water pH

Ranchu goldfish prefer slightly alkaline water with a pH between 7.0-8.0. You can use a pH testing kit to monitor the pH level and adjust it as necessary.

Avoid large fluctuations in pH, as this can also stress your fish.

Water Hardness

Ranchu goldfish prefer moderately hard water with a hardness level between 150-300 ppm. You can use a water hardness testing kit to monitor the hardness level and adjust it as necessary.

Soft water can cause health problems for your fish, so it is important to maintain the proper level of hardness.

Water Changes

Regular water changes are essential for maintaining good water quality in your ranchu goldfish tank. Aim to change 20-30% of the water in your tank every week.

This will help remove any excess waste and debris, and keep the water fresh and clean for your fish.

I personally find that doing water changes on a regular schedule helps me remember to keep up with it. I like to do mine on Sundays, so I don’t forget.

Tank Maintenance

Maintaining a clean and healthy tank is crucial for the well-being of your ranchu goldfish. Here are some tips to help you keep your tank in top condition:

First, make sure to perform regular water changes. Aim to change at least 20% of the water in your tank every week to keep the water clean and fresh.

You can use a siphon to remove any debris or waste from the bottom of the tank during water changes.

Second, keep an eye on the water parameters. Test the water regularly for pH, ammonia, nitrite, and nitrate levels.

You can use test strips or a liquid test kit to do this. If any of the levels are off, take action to correct them. For example, if the pH is too low, add some baking soda to raise it.

Third, clean the tank and equipment regularly. Use a non-toxic cleaner to wipe down the inside of the tank and any decorations or equipment. Make sure to rinse everything thoroughly before putting it back in the tank.

Finally, keep an eye out for any signs of illness or disease in your fish. If you notice anything unusual, such as lethargy or loss of appetite, take action immediately.

You can consult with a veterinarian who specializes in fish health or a knowledgeable pet store employee for advice.

Personally, I find that maintaining a clean and healthy tank is not only important for the health of my ranchu goldfish, but also for my own enjoyment of watching them swim and play in a beautiful environment. With a little bit of effort and care, you can ensure that your goldfish thrive in their home.

Tank Mates

Compatible Fish Species

If you’re considering adding some tank mates to your ranchu goldfish aquarium, there are several species that are known to coexist peacefully with them. Some good options include:

  • White Cloud Mountain Minnows
  • Otocinclus Catfish
  • Corydoras Catfish
  • Bristlenose Plecos

These fish are all small, peaceful, and won’t compete with your ranchu goldfish for food or territory. Plus, they can help keep your tank clean by eating algae and other debris.

Incompatible Fish Species

While there are plenty of fish that can live happily with your ranchu goldfish, there are also some species you should avoid. These include:

  • Aggressive or territorial fish, such as cichlids or bettas
  • Fast-swimming fish that may stress out your ranchu goldfish, such as danios or tetras
  • Fish that require different water conditions, such as saltwater fish or tropical fish that prefer warmer temperatures

Adding incompatible fish to your ranchu goldfish tank can lead to stress, aggression, and even illness. Stick to compatible species to ensure a peaceful and healthy environment for your fish.

How Many Ranchu Goldfish Should I Get?

When it comes to how many ranchu goldfish you should keep in your tank, a good rule of thumb is to have no more than one inch of fish per gallon of water.

However, keep in mind that ranchu goldfish can grow quite large, so you’ll need a larger tank than you might think.

Additionally, ranchu goldfish are social creatures and thrive in groups, so it’s best to keep at least two or three together. Just be sure to provide plenty of space and hiding places to prevent overcrowding and territorial disputes.

Personally, I’ve found that keeping a small group of ranchu goldfish with a few compatible tank mates is a great way to create a vibrant and interesting aquarium.

Just be sure to do your research and choose your fish carefully to ensure a happy and healthy environment for all your aquatic friends.


Ranchu goldfish are known for their round, chubby bodies and their unique head shape.

To keep your ranchu goldfish healthy and happy, it is important to provide them with a well-balanced diet. Here are some tips on what to feed, feeding frequency, and other helpful tips:

What To Feed

When it comes to feeding your ranchu goldfish, variety is key. You can feed them a combination of dry and live foods. Some popular options include:

  • Flake food
  • Pellets
  • Frozen or live brine shrimp
  • Frozen or live bloodworms

It is important to avoid overfeeding your ranchu goldfish, as they are prone to obesity. Be sure to monitor their food intake and adjust accordingly.


Feed your ranchu goldfish small amounts of food 2-3 times a day. It is best to feed them at the same time each day to establish a routine.

Overfeeding can lead to health problems, so be sure not to exceed the recommended amount.


Here are some additional tips to keep in mind when feeding your ranchu goldfish:

  • Remove any uneaten food after 5-10 minutes to prevent water quality issues.
  • Consider adding some fresh vegetables to their diet, such as peas or lettuce.
  • Feed your ranchu goldfish in a designated area to prevent food from floating away and causing water quality issues.

Remember, a healthy diet is essential for the overall health and well-being of your ranchu goldfish. By providing them with a variety of foods and monitoring their intake, you can help ensure they live a long and happy life.

Personally, I have found that my ranchu goldfish enjoy a mix of pellets and live brine shrimp.

I also like to switch up their diet with some fresh veggies every now and then. It’s important to experiment with different foods to find what works best for your fish.

Common Diseases


Goldfish are generally hardy and healthy fish, but they are still susceptible to a few common diseases.

One of the most common diseases in ranchu goldfish is swim bladder disorder, which affects the fish’s ability to control its buoyancy.

Other common diseases include bacterial infections, fungal infections, and parasitic infections.


Swim bladder disorder can cause your ranchu goldfish to float upside down or sink to the bottom of the tank.

Bacterial infections can cause your fish to have red or white sores on their body, while fungal infections can cause a white cotton-like growth on their body.

Parasitic infections can cause your fish to have white spots or a slimy coating on their body.


If you notice any symptoms of disease in your ranchu goldfish, it’s important to take action quickly.

Swim bladder disorder can be treated by feeding your fish a diet high in fiber or by adding aquarium salt to the water.

Bacterial infections can be treated with antibiotics, while fungal infections can be treated with antifungal medication. Parasitic infections can be treated with medication specifically designed to kill parasites.


The best way to prevent disease in your ranchu goldfish is to keep their tank clean and well-maintained. Make sure to perform regular water changes and keep the water temperature consistent.

Avoid overcrowding the tank and make sure to quarantine any new fish before adding them to the tank. It’s also important to feed your fish a balanced diet and avoid overfeeding.

Personally, I have had a ranchu goldfish that suffered from swim bladder disorder. It was heartbreaking to see my fish struggle to swim and control its buoyancy.

However, with proper treatment and care, my fish was able to recover and live a healthy life.

Signs of a Healthy Ranchu Goldfish

When it comes to taking care of your ranchu goldfish, one of the most important things to look out for is their health. Here are some signs that your ranchu goldfish is healthy:

  1. Active and alert: Your ranchu goldfish should be swimming around and exploring their tank. If they are lethargic or spending a lot of time at the bottom of the tank, it could be a sign of illness.
  2. Clear eyes: Your ranchu goldfish’s eyes should be clear and free from any cloudiness or discoloration.
  3. Smooth scales: Your ranchu goldfish’s scales should be smooth and free from any bumps or lumps.
  4. Healthy fins: Your ranchu goldfish’s fins should be intact and not torn or frayed.
  5. Good appetite: Your ranchu goldfish should be eating regularly and showing interest in their food.

If you notice any changes in your ranchu goldfish’s behavior or appearance, it’s important to take action quickly.

This could mean testing the water quality in their tank, adjusting their diet, or seeking the advice of a veterinarian.

Personally, I’ve found that keeping a close eye on my ranchu goldfish’s behavior and appearance has helped me catch any potential health issues early on.

By staying vigilant and taking action quickly, I’ve been able to keep my ranchu goldfish happy and healthy for years.

Signs Your Ranchu Goldfish is Sick

If you’re a ranchu goldfish owner, it’s important to keep an eye out for signs that your fish may be sick. Here are some common signs to watch for:

  1. Loss of appetite: If your fish isn’t eating like it used to, it could be a sign of illness.
  2. Swimming erratically: If your fish is swimming sideways or upside down, it could be a sign of swim bladder disease.
  3. Gasping for air: If your fish is gasping for air at the surface of the water, it could be a sign of poor water quality or a respiratory problem.
  4. Cloudy eyes: If your fish’s eyes appear cloudy or hazy, it could be a sign of bacterial or fungal infection.
  5. White spots: If your fish has white spots on its body, it could be a sign of ich, a parasitic infection.

If you notice any of these signs, it’s important to take action quickly to help your fish recover. You may want to consult with a veterinarian who specializes in fish care to determine the best course of treatment.

Personally, I once noticed that one of my ranchu goldfish was swimming sideways and seemed to be struggling to stay upright.

I did some research and learned that this could be a sign of swim bladder disease.

I adjusted the fish’s diet and made sure the water quality was optimal, and after a few days, the fish seemed to be back to normal. It’s important to pay attention to your fish’s behavior and take action if you notice anything out of the ordinary.


ranchu goldfish 2

Breeding Setup

Before you start breeding ranchu goldfish, you need to set up a breeding tank.

The breeding tank should be at least 20 gallons and should have a sponge filter, a heater, and a cover. The water temperature should be around 70-75°F, and the pH should be between 7.0-7.5.

You should also provide some hiding places for the fish, such as plants or breeding cones. The breeding cones should be placed in the tank at least a week before breeding to allow the fish to get used to them.

How To Breed

Once the breeding tank is set up, you can introduce the male and female ranchu goldfish. It’s best to have one male and one female in the tank.

The male will start chasing the female around the tank, and they will eventually start spawning.

The female will lay eggs on the breeding cone or other surfaces, and the male will fertilize them. After spawning, you should remove the adult fish from the breeding tank to prevent them from eating the eggs.


After the eggs are laid, they will hatch in about 3-4 days. The fry will start swimming freely after about a week. You should feed them small amounts of baby brine shrimp or powdered fish food several times a day.

It’s important to keep the water in the breeding tank clean by doing regular water changes. You should also monitor the water parameters to make sure they are stable.

As the fry grow, you can start feeding them larger foods, such as daphnia and crushed pellets. You should also start removing any deformed or sickly fish to prevent them from infecting the others.

Breeding ranchu goldfish can be a rewarding experience, but it requires patience and dedication. With the right setup and care, you can raise healthy and beautiful fish.

Personally, I found breeding ranchu goldfish to be a challenging but rewarding experience. Watching the eggs hatch and the fry grow was truly amazing. It’s important to remember that not all eggs will hatch and not all fry will survive, but with perseverance, you can raise a healthy and happy batch of fish.

Product recommendations for Ranchu Goldfish:

  1. Hikari Lionhead Pellets – These pellets are specifically designed for Ranchu Goldfish, providing a balanced diet that is high in protein and essential nutrients.
  2. Seachem Prime – This water conditioner is perfect for Ranchu Goldfish, neutralizing harmful toxins and chemicals in the water and keeping your fish healthy and happy.
  3. Aqueon LED Aquarium Light Fixture – This high-quality LED light fixture is perfect for Ranchu Goldfish, providing bright and energy-efficient lighting that will help your fish thrive.
  4. API Freshwater Master Test Kit – This comprehensive test kit is perfect for Ranchu Goldfish owners, allowing you to monitor the water quality of your aquarium and ensure that your fish are healthy and happy.
  5. Zoo Med Nano 10 External Canister Filter – This powerful and efficient canister filter is designed for small aquariums and is perfect for keeping the water in your Ranchu Goldfish tank crystal clear.
  6. Tetra Whisper Air Pump – This powerful and reliable air pump is perfect for Ranchu Goldfish, providing a steady flow of oxygenated water that will keep your fish healthy and happy.
  7. API Stress Coat Water Conditioner – This aquarium conditioner is perfect for Ranchu Goldfish, reducing stress and promoting healing in your fish by forming a protective slime coat on their skin.
  8. Fluval Bug Bites Goldfish Formula – This high-quality fish food is perfect for Ranchu Goldfish, providing a balanced diet that is rich in protein and essential nutrients.
  9. Fluval Biomax Bio Rings – These bio rings are perfect for Ranchu Goldfish, providing efficient biological filtration that will keep the water in your aquarium clean and clear.


Now that you have read this comprehensive guide on Ranchu Goldfish care, you are well-equipped to provide the best possible care for your fish. Remember to keep the water clean and well-oxygenated, feed them a balanced diet, and maintain a suitable environment.

By following the tips and advice outlined in this article, you can ensure that your Ranchu Goldfish live a long and healthy life. Remember to monitor their behavior and appearance regularly and seek veterinary attention if you notice any signs of illness.

As a proud owner of Ranchu Goldfish, I can attest to the joy and satisfaction that comes with providing them with the best care possible. Watching them swim around happily in their tank is truly a rewarding experience. With a little effort and dedication, you too can enjoy the beauty and companionship of these wonderful fish.


Here are some common questions about caring for ranchu goldfish:

Q: How often should I feed my ranchu goldfish?

A: You should feed your ranchu goldfish 2-3 times a day, but only give them as much food as they can eat in 2-3 minutes. Overfeeding can lead to health problems and a dirty tank.

Q: What should I feed my ranchu goldfish?

A: Ranchu goldfish are omnivores and should be fed a balanced diet of both plant and animal matter. You can feed them flakes, pellets, frozen or live food such as brine shrimp, bloodworms, or small pieces of vegetables like peas or lettuce.

Q: How often should I change the water in my ranchu goldfish tank?

A: You should change 20-30% of the water in your tank every week to keep it clean and healthy for your fish. Make sure to use a water conditioner to remove chlorine and other harmful chemicals from tap water.

Q: What temperature should the water be for my ranchu goldfish?

A: Ranchu goldfish prefer cooler water temperatures between 65-75°F (18-24°C). Make sure to use a thermometer to monitor the water temperature and adjust your heater as needed.

Q: Can I keep my ranchu goldfish with other fish?

A: Yes, but make sure to choose fish that are compatible with ranchu goldfish and won’t nip at their fins or bully them. Avoid keeping them with aggressive or territorial fish. It’s also important to make sure your tank is big enough to accommodate all the fish comfortably.

Overall, caring for ranchu goldfish can be a rewarding and enjoyable experience. With proper care and attention, your ranchu goldfish can live a long and healthy life.

Reference: Wikipedia.


Hi there! My name is Jacob, and I'm the founder of this Pet people blog that talks all about aquarium and fishkeeping. I've been passionate about fish and aquatic life since I was a kid, and I've spent countless hours learning about different species, their habitats, and how to create the perfect environment for them to thrive in.

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