Ranchu Goldfish, or Carassius auratus, is a variety of freshwater Fancy Goldfish. Referred to as the “king of Goldfish,” these beautiful fish are a favorite among hobbyists. Are you wondering if a Ranchu is the right fish for you? In this guide, find everything you need to know about Ranchu Goldfish.
History of Ranchu Goldfish
Modern Ranchus are considered a Japanese variety of Fancy Goldfish, but their origins can be traced back to China. Ranchus were first developed from Lionhead Goldfish. They were further developed in Japan beginning in the late 1800s but did not begin to resemble modern Ranchus fully until the early 1900s.
Appearance of Ranchu Goldfish
Ranchu Goldfish have a short, round, egg-shaped body with an arched or curved appearance and large, bulbous heads. Two characteristic features of Ranchus are their lack of dorsal fins and the presence of fleshy, raspberry-like head growths. While Ranchus can be easily mistaken for Lionheads, Ranchus have higher arched backs. Ranchus also have splayed caudal fins with three to four separate, rounded lobes. Lionheads have caudal fins that are more similar to Fantail Goldfish.
Ranchus can be found in various colors, including red, white, orange, and blue, and several color combinations, including calico, red and white, back and red, and black and white. Sometimes, they may have red scales with white edges. The color of a Ranchu Goldfish can change as it matures, sometimes completely. White is the color that most commonly shows up later in life. Ranchus were initially bred as metallic-scaled fish but can come in nacreous or matte scalation patterns as well.
The typical size of a full-grown Ranchu is five to eight inches long. Because of the shape of their bodies and lack of dorsal fins, Ranchus can have difficulty swimming. Ranchu Goldfish are incredibly delicate and typically not recommended for beginner Goldfish hobbyists.
Caring For Ranchu Goldfish
Though Goldfish are considered low-maintenance pets, regular care and tank upkeep are essential. The right environment and diet can help your Ranchu Goldfish stay happy and healthy.
Tank Setup
Tank Size
When choosing a tank for your Ranchu Goldfish, it’s recommended to select one at least 20 gallons in size. If you have the space, bigger is always better. Larger tanks will help keep the water cleaner for longer. Plus, Ranchus are clumsy swimmers, so extra space for swimming will keep them from bumping into things and potentially injuring themselves. A tank that is too small can contribute to stress, negatively impact water quality, and increase the chance of illness and disease.
If you house more than one Ranchu in your tank, the size should be increased by 10 gallons per fish. To add other varieties, increase the tank size by one gallon per 1” of fish. Make sure you use the estimated full-grown size of the fish when making these calculations. Goldfish require well-oxygenated water. For this reason, a tank with ample surface area is a great choice. This will allow for gaseous exchange and help oxygenate the water.
Water Parameters
Goldfish are hardy fish and can tolerate a good range of temperatures and conditions. However, Ranchus are a bit more sensitive to fluctuations in water parameters. The optimal water temperature for Ranchu Goldfish is 65-72°F.
A strong filtration system is essential. Ranchus, like all types of Goldfish, produce a lot of waste. It’s recommended to choose a filter that circulates with a GPH (gallons per hour) rate of at least four times the volume of your tank. For example, if you have a 30-gallon tank, your filter should have a minimum GPH rate of 120. Because Ranchus are not strong swimmers, they do much better in slow-moving water. Therefore, it’s a good idea to choose a low-flow filter or one with adjustable flow settings. If the flow is still too strong, you can reduce it in other ways.
Ranchus prefer a neutral pH between 6.5-7.5 but will tolerate a range between 6-8. Water hardness should be between 5-19 degrees of general hardness or 89-339 parts per million (ppm). Be sure to purchase a standard freshwater aquarium test kit to keep track of these levels. Water changes of 25-35% should be performed weekly to keep your water clean and your fish healthy.
|
Water parameters |
Values |
|
Temperature |
65-72°F |
|
pH |
6.5-7.5 |
|
GH (general hardness) |
5-19 dGH or 89-339 ppm |
|
KH (carbonate hardness) |
4-8 dKH or 70-140 ppm |
|
Ammonia |
0 ppm |
|
Nitrite |
0 ppm |
|
Nitrate |
Below 30-40 ppm |
Tank Decorations
When decorating your tank, it’s important to remember that Ranchu Goldfish are very delicate. Avoid sharp edges that could potentially injure your Ranchu. This also factors into your choice of substrate. It’s a good idea to stay clear of rough or sharp substrates, including certain types of gravel. Sand or smooth pebbles are ideal for Ranchu tanks. Given the clumsy nature of Racnhus, try not to overclutter your tank and create too many obstacles for your fish.
Adding plants to your tank is a great way to give it a more natural look and increase oxygen levels. However, Goldfish love to dig and eat plants. Many plants won’t do well in a Goldfish tank. If you want to add plants to your tank, epiphytes, including Anubias, Java Fern, and Java Moss, are the best choice. If you decide to go the artificial route, silk plants are much safer than plastic ones.
Tank Mates
Ranchus are social, calm, and do well in a community. However, they’re also sensitive and not strong swimmers. Because of this, they can be a target for more aggressive fish. You’ll want to avoid larger, aggressive or territorial fish, fin-nippers, and fast fish of all sizes, including Bettas, Barbs, and Cichlids. Fin-nippers will target the flowing tailfin on Ranchus, and aggressive and fast-swimming fish will compete for food. Tropical fish are also unsuitable tank mates, given their different temperature requirements.
Other Fancy Goldfish varieties make excellent tank-mates for Ranchus, including Lionhead Goldfish, Bubble Eye Goldfish, Pearlscale Goldfish, and Black Moor Goldfish. Some other good options are Guppies, Mosquitofish, Platies, and Zebra Danios.
Feeding
Like all Goldfish varieties, Ranchus are omnivores and will consume both plant- and protein-based foods. Ranchus are susceptible to swim bladder issues, which can be exacerbated by gulping too much air at the water’s surfac–a common problem with floating foods. Because of this, sinking pellets are the best choice for Ranchus. Choosing a formula with minimal filler will help keep your fish healthy and limit the amount of water in your tank. Adult Ranchus should be fed once or twice daily, while younger Ranchus may need an extra feeding.
You can supplement their standard feed with live or freeze-dried protein sources, including bloodworms, brine shrimp, and tubifex. Freeze-dried options are safer, as live foods can contain parasites and bacteria that can lead to illness. If you choose live foods, make sure you’re purchasing from a reputable source. Before feeding your fish live food, remove the food from the water it is packaged in.
Goldfish are notorious overeaters and will continue to eat as long as food is offered. To avoid overeating, only give your fish what they can eat in 2-3 minutes. However, Ranchus may take longer to feed due to poor vision from their headgrowth and may need a little more time to find their food than other Goldfish varieties. You can learn more about feeding Fancy Goldfish in our guide to Feeding Your Fancy Goldfish.
Health Concerns
Ranchus are among the most sensitive of freshwater fish. They are highly bred and tend to be more susceptible to health problems than other varieties of Goldfish. Swim Bladder Disease is the most common ailment impacting Ranchus. You can protect your Ranchu from swim bladder issues by avoiding overfeeding, feeding your fish high-quality feed, and keeping the water in your tank clean. Other common problems include Ich, Velvet Disease, and Fin Rot. The good news is that many diseases and illnesses can be avoided by monitoring water conditions, performing regular water changes, limiting stress, and keeping the water in your tank well-maintained. You can learn more about Goldfish Diseases in our Comprehensive Guide to Goldfish Diseases.
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