Ranchu Goldfish Care: From Tank Setup to Feeding, A Complete Guide

Ranchu goldfish, also known as the “king of goldfish,” is a popular ornamental fish that has been prized for centuries. Originating in Japan, this goldfish was first bred during the 18th century as a mutation of the lionhead goldfish.

Proper care is essential for the health and well-being of Ranchu goldfish. Without proper care, they are prone to stress, disease, and early death. This is why it’s essential for pet owners to learn how to provide the best possible care for their Ranchu goldfish.

The purpose of this blog post is to provide a comprehensive guide on Ranchu goldfish care, including their diet, tank setup, water parameters, maintenance, size, and lifespan.

The Origin of Ranchu Goldfish

Ranchu goldfish is a type of fancy goldfish that originated in Japan. It is believed to have been first developed in the late 1800s by crossbreeding Lionhead goldfish and the Japanese bred Goldfish called “Bikini”.

The early versions of Ranchu goldfish were known as “Edo Ranchu” and were bred in the Edo period of Japan. The breeding of Ranchu goldfish became popular among Japanese hobbyists in the 1900s. The fish was named after its hump-shaped back that resembles a traditional Japanese Sumo wrestler’s hump.

These goldfish became increasingly popular in Japan, and their breeding continued to evolve, with breeders selectively breeding for desirable traits such as coloration, body shape, and finnage. Eventually, the fish was exported to other parts of the world, including Europe, North America, and Asia.

Today, Ranchu goldfish are a popular type of fancy goldfish and are highly sought after by collectors and enthusiasts. They come in a wide range of colors and patterns, and their unique body shape makes them a distinctive addition to any aquarium.

The Size, Lifespan, and Appearance of Ranchu Goldfish

Ranchu goldfish are small to medium-sized fish, typically reaching about 6-8 inches (15-20 cm) in length, although some specimens can grow up to 10 inches (25 cm) in length with proper care. They have a lifespan of around 10-15 years, although some have been known to live up to 20 years in ideal conditions.

They have a unique and distinctive appearance. They are known for their hump-shaped back, which is one of their most recognizable features. The hump, also known as the wen, is a fleshy growth on the back of the fish’s head.

Ranchu goldfish come in a variety of colors, including red, white, black, yellow, and blue. Their fins are typically short and rounded, and they have a rounded body shape.

Their scales are smooth and shiny, and their eyes are large and protruding. The size and shape of their wen can vary, and some specimens have a large, well-developed wen that covers their entire head, while others have a smaller, less prominent wen.

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Dietary Requirements of Ranchu Goldfish

A healthy and balanced diet is crucial for the overall health of your Ranchu goldfish. These fish are omnivores, meaning they eat both plant and animal matter. In the wild, they feed on small crustaceans, insects, and other aquatic creatures, as well as algae and other plant matter.

When it comes to feeding your Ranchu goldfish, there are many options available. Commercially available fish food is a great starting point, but it’s important to choose a high-quality food that is specifically designed for goldfish.

Pellets or flakes that are high in protein and fiber are best. Supplementing their diet with fresh or frozen foods such as bloodworms, brine shrimp, and vegetables can also be beneficial.

They should be fed small amounts multiple times a day instead of one large meal. Overfeeding can lead to health problems and poor water quality. As a general rule, feed your Ranchu goldfish only what they can eat in 2-3 minutes. It’s also a good idea to fast them once a week to give their digestive system a break.

How to Set up Tank for Ranchu Goldfish?

Tank setup is a crucial aspect of providing proper care for Ranchu goldfish. These fish require a spacious tank with appropriate filtration, water quality, and decorations to thrive in a healthy environment.

Appropriate Tank Size

Ranchu goldfish can grow quite large, so it’s important to provide them with a tank that is appropriately sized. As a general rule, a tank that can hold at least 20 gallons of water is the minimum recommended size for one Ranchu goldfish.

Keep in mind that the larger the tank, the better, as it will provide more swimming space and allow for better water quality.


Proper filtration is essential for maintaining good water quality in your Ranchu goldfish tank. A filtration system should be able to process the volume of water in the tank at least 3-5 times per hour. Canister filters, hang-on-back filters, and sponge filters are all good options for a Ranchu goldfish tank.

Water Quality Considerations

Ranchu goldfish are sensitive to changes in water quality, so it’s important to monitor the tank’s water parameters regularly.

The optimal water temperature for Ranchu goldfish is between 68-74°F (20-23°C), with a pH level between 7-8.5 and a water hardness between 150-300 ppm. A water testing kit can help you monitor these levels and ensure that they stay within the appropriate range.

Decoration and Substrate Options

Ranchu goldfish enjoy having plenty of hiding spots and places to explore in their tank. Decorations such as rocks, caves, and plants can provide this type of enrichment.

It’s essential to choose decorations that are safe for your fish and won’t leach harmful chemicals into the water. For substrate, sand or small gravel are good options as they are easy to clean and won’t trap debris like larger gravel can.

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What are Some Good Tank mates for Ranchu Goldfish?

Ranchu goldfish are generally peaceful and social fish, so they can coexist well with other goldfish and peaceful community fish. Always choose tank mates that are compatible with their needs and temperament. Here are some good tank mates for Ranchu goldfish:

Other goldfish

Ranchu goldfish can live happily with other fancy goldfish such as Orandas, Ryukins, and Fantails. However, it’s important to avoid mixing them with single-tail goldfish such as Common Goldfish or Comet Goldfish as they are more active swimmers and can outcompete Ranchus for food.

Cherry shrimp

Cherry shrimp are small and peaceful invertebrates that can coexist with Ranchu goldfish. They are also beneficial for keeping the tank clean by consuming algae and other debris.

Mystery snails

Mystery snails are another peaceful and beneficial tankmate for Ranchu goldfish. They help clean the tank by consuming algae and leftover food, and their shells provide a source of calcium for the goldfish.

Corydoras catfish

Corydoras catfish are peaceful bottom-dwelling fish that can coexist with Ranchu goldfish. They help clean the substrate by consuming uneaten food and other debris, and their social behavior can be entertaining to watch.


Guppies are small and peaceful community fish that can add a pop of color to the tank. They are also good at consuming any leftover food and are generally compatible with Ranchu goldfish.

A Beginner-Friendly Care Guide for Ranchu Goldfish

What Is the Proper Tank Setup for Ranchu Goldfish?

When it comes to setting up a quarantine tank for Ranchu Goldfish, there are a few important factors to consider. Firstly, choose an appropriate tank size, ideally around 20-30 gallons, with a filtration system to ensure water quality. Provide hiding spots and soft surfaces to prevent fin damage. Maintain stable water temperature and introduce new fish to the quarantine tank before adding them to the main tank. This vital step helps prevent the spread of diseases and safeguards the health of your Ranchu Goldfish.


Taking care of Ranchu Goldfish requires a lot of effort, but it is worth it in the end. Whether it’s maintaining their diet, setting up their aquarium, or monitoring their health, every aspect of their care is important. If you follow these guidelines, you can create a healthy and happy environment for your Ranchu Goldfish to thrive in.

This will not only benefit your Goldfish but also bring joy and satisfaction to you as a pet owner. Remember, taking care of any living thing requires patience, perseverance, and dedication, but the rewards are immeasurable.

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