Fish Files: Ranchu Goldfish (Carassius auratus) King of the Goldfish

Ranchu (Carassius auratus) is a Fancy Goldfish type that was created in Japan, they are one of the oldest fancy goldfish to date. Nicknamed “King of Goldfish” by the Japanese as they are highly prized with some selling for hundreds of dollars. They were developed from the Lionhead variety and are distinct as they lack any dorsal fin. The scales are metallic and come in a wide variety of colours from white to black.

When judged in competitions the Ranchu is judged from a top view by the Japanese, however the Chinese judge from a side view. Due to these judging styles, they are bred to have a large belly, large wen (head growth) and high sitting eyes.

Ranchu Care


Goldfish can get quite large, with the Ranchu growing to around 5-8” long. They will need an aquarium of at least 50-75 litres, kept at around 18.3 to 22.2° C. A good rule is to have at least 40 litres per Goldfish. They will need a filtration system, a light and an air pump can also be added for extra water aeration. Ensure that both the air pump and filter are not too powerful as these fish are poor swimmers and will struggle with a strong current. We have a large range of internal, external and hang-on filters, all of which will be suitable for a Goldfish set-up depending on the size of your tank (the larger the tank, the bigger the filtration system needed). Hang-on filters have the added benefit of creating a nice natural waterfall/trickle into the tank so these are ideal at not creating too much water flow. These Goldfish are not well suited to pond life as fluctuating temperatures can put them into shock, their limited movement also makes them easy prey to any potential predators. 


These Fancy goldfish have an average lifespan of around 10-15 years, with some being recorded living to a whopping 20 years!


The Ranchu should be kept with other slow-moving Fancy goldfish, nothing too fast that could out-compete them for food. Some good companions include the Pearlscale, Lionhead, Bubble and Telescope eye.


They will happily accept flake foods however, frozen foods should be offered – blood worm is very popular with goldfish.

What are the main differences between a Ranchu and Lionhead?

• Ranchu have a higher curved back than Lionheads.

• Ranchu have a thicker “stubby” body compared to the Lionhead.

• Lionheads have a larger “wen” growth.