Shubunkin Goldfish Guide (Facts, Care, Lifespan)

Shubunkins are a single-tailed goldfish species that came about by breeding together the common goldfish, and calico telescope eye goldfish. The result is a unique, beautiful goldfish with nacreous (having a mother-of-pearl effect) coloring in various combinations of orange/gold, red, white, silver, blue, and black.

They originated in Japan around the year 1900, but there are now other commonly found varieties – the London shubunkin and the Bristol shubunkin. The Japanese (sometimes referred to as American) shubunkin is perhaps the most popular, with a long body shape and a well-developed, pointed tail fin.

London shubunkins have shorter fins, similar to those of common goldfish, and Bristol shubunkins possess rounded caudal fins. No matter the variety, shubunkins are quite hardy, active, and playful.

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Shubunkin Goldfish Maximum Lifespan & Size

Shubunkins reach adulthood by the age of two years, at which point they will have reached a maximum size of up to 18 inches in length. If kept in an aquarium, they may only grow up to 10 inches in length, depending upon the size of the aquarium and the number of other fish present. They can grow up to a foot within their first year of life, again depending on whether they’re kept in a tank or a pond and the size of either of these.

The maximum life expectancy of shubunkins is quite long, up to 30 years, although closer to 15-20 years in a pond and 10 years in an aquarium are considered average. As with any fish, exact growth rate depends on water quality, genetics, temperature, feeding rate, and overall diet.

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Shubunkin Feeding & Nutrition – What’s the Best Food?

Shubunkins are omnivorous, and as such need a varied diet, as well as a high quality goldfish fish feed. As with most carp relatives, shubunkins require a diet that’s rich in protein – things like brine shrimp, bloodworms, krill meal, and other high protein foods should compose about 30 to 50% of their diet. As protein needs are higher for younger fish, fry and juveniles should be fed at or near 50% protein, with this decreasing closer to the 30% mark once adulthood is reached. The remaining 50 to 70% should be plant based and include foods like spinach, lettuce, shelled cooked peas, spirulina, cucumber, watermelon, water hyacinth, oranges, and tomatoes.

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They will also likely munch on any aquatic insects and plants that are present in the pond. Their low lipid and fiber needs (both of which are approximately 5%) as well as their vitamin and mineral requirements are easily met by feeding either these fresh or frozen foods, or via feeding them quality fish flakes or pellets supplemented by the aforementioned fresh or frozen options. Flakes or pellets and fresh, frozen, or freeze-dried proteins can be fed several times daily, veggies can be fed once per day, and fruits can be provided every three days or so. Remember to only feed your fish as much as they will eat in a short two minute span to avoid overfeeding.

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Shubunkin Goldfish Tank Size & Pond Stocking

If kept in a tank, you should have at least 30 gallons of water for your first shubunkin and then a minimum of an additional 10 gallons for each added shubunkin. An easy rule of thumb to remember is that one inch of fish equates to a gallon of water, minimum. It is important to note that this rule only applies to juvenile fish as adult fish consume more oxygen and generate more waste, and therefore require more water to maintain healthy environmental quality.

In ponds, you can follow the same rule of thumb, but as you’re likely to have more fish and plants in a pond than in an aquarium, having closer to 100 gallons of water for the first shubunkin following by an additional 20-30 for each added shubunkin to prevent overcrowding will offer the best combination of space and improved water quality. The depth of the pond should be at least 3 feet to reduce the risk of the pond freezing during the winter and allow for fish to hide from predators and seek denser, warmer, deeper water during cold periods.

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Shubunkin Wintering, Hardiness & Water Quality

One of the hardier pond fish species, shubunkins do well in a pH ranging from 6 to 8 and water temperatures between 65 and 75° F (18 to about 23° C). Slight fluctuations outside of these ranges can be tolerated, so long as they do not occur too suddenly or frequently. If waters fall near 50° F in the winter, shubunkins, like other goldfish, can go into a state of torpor for several months. Though shubunkins are of course freshwater fish, one study found that they can tolerate salinity levels up to 2 ppm without harm to health, so long as this salinity change occurs over several hours rather than abruptly. This is helpful information to know in case a salt bath is ever needed to treat infection or disease.

During winter, it’s always best to ensure you install a de-icer or electric heater to keep a hole in the ice open for shubunkins to breath and for gas exchange to take place. Although shubukins can survive cold conditions, they will struggle if oxygen drops to lower levels, which can be common if a pond freezes solid. Check out our guides on both electric de-icers and heaters below:

• Best Shubunkin Goldfish De-icers
• Methods to Heat Goldfish Ponds

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Shubunkin Goldfish Tank Mates & Group Size

Shubunkins are social, playful fish that do best when kept with two or more of their own kind. Keep in mind that, when kept in ponds with plenty of space and high-quality food, shubunkins can grow quite large, so try starting off with only 3 to 5 shubunkins to ensure that you have enough space for them as they mature into adulthood. This number will, of course, depend upon the size of your pond and can be altered depending upon that as well as your personal preference and any other fish species present.

They are amiable fish, and do will with koi and most other goldfish varieties so long as they are of similar size. Larger fish may nip at or even eat shubunkins, though their athleticism will make this a bit difficult.

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How to Design Shubunkin Goldfish Ponds

As stated previously, the deepest part of the pond should be a minimum or 3 feet to allow for hiding and overwintering. Shubunkins don’t do well in full sunlight, so be sure to incorporate hiding places via things like PVC pipes, fish shelters, and plants. Gravel or a similar substrate will work best in the bottom of the pond, as shubunkins have been known to root around and can cause turbidity if small-grained substrates like sand or silt are used. To keep plants from being uprooted while shubunkins explore and dig about, you can place them in weighted pots or weigh them down with metal washers if their root systems are not well-developed.

You can also place large rocks around the roots of plants to prevent them from being eaten or uprooted. Shubunkins, like many other goldfish varieties, are not picky eaters and are likely to nibble on plants. When incorporating plants in and around your pond, please be sure to consult our list of plants that are toxic to pond fish!

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Common Shubunkin Problems, Illness & Diseases

Being a hardy fish, shubunkins don’t have many health issues naturally. If health issues do arise, they are likely due to environmental conditions. Make certain that there is plenty of dissolved oxygen, temperature and pH are within the optimum range, 25% water changes are conducted weekly, and pollutants like ammonia are kept to an absolute minimum. Fin rot has been known to affect shubunkins, but only in cases of poor water quality or pond overstocking (which leads to poor water quality).

Swim bladder issues can also impact shubunkins, but again this is most often due to care factors such as water quality, poor diet, or water that is too warm or cold. Occasionally, it may be due to a bacterial or parasitic infection that could have been introduced from an outside source, such as a bird landing in your pond or runoff from agricultural fields. Most often, shubunkins with infections were reared on fish farms that are overstocked, allowing for disease to develop and spread very easily.

Should You Quarantine New Subunkin?

Anytime you obtain a new fish from a store, whether it’s a shubunkin or not, be sure to quarantine it from the rest of your fish in a separate tank for a few days to assess its health and perform any necessary treatments. Overall, shubunkins don’t require much to be healthy, so as long as you maintain proper water quality in combination with a balanced diet, your shubunkins should live a long and hearty life!

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Shubunkin Breeding Behaviour & Requirements

Shubunkins can breed when there are five or more individuals, but prefer larger groups as they are social animals. If interested in spawning, you’ll notice males chasing females about non-aggressively and the colors of both sexes may become more intense as hormone production ramps up.

To induce breeding, you’ll want to gradually drop the water temperature down to about 60° F and keep the water at this temperature for a day or two. Then, increase the water temperature by about 2° F per day. This temperature shift will sort of “trick” their system into thinking there’s been a seasonal shift and that it’s time to mate.

Shubunkins generally breed once water temperatures are between around 68 and 74° F. Increase protein intake from the normal 30% amount for adults up to 50% and feed several times per day, as this will stimulate females to produce and drop eggs that can then be fertilized by males. During this time of increased feeding, you’ll want to perform daily water changes of 20-25% as any uneaten food will decay and diminish water quality. You’ll also want to be sure to have a variety of submerged as well as floating plants, as adult shubunkins will find these to be ideal for breeding habitat both due to protective cover from predators as well as providing a natural surface to lay eggs on.