Species Profile: Koi and Goldfish
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SRAC Publication No. 7201
VI
PR
September 2004
Species Profile: Koi and Goldfish
Craig A. Watson, Jeffrey E. Hill and Deborah B. Pouder*
Most people are familiar with the fancy goldfish. Koi generally have common carp can be abundant in
beautiful and often strikingly elongated bodies, but goldfish slow-moving rivers and reser-
unusual koi and goldfish used as may have bodies that are short voirs. Both are considered cool-
ornamental fish in ponds and and round like an egg or ball. water fishes, yet they can survive
aquaria. Both are species of carp In addition to the ornamental in a wide range of water tempera-
whose wild types are an unspec- varieties, both species are pro- tures.
tacular grey-green or brownish duced, with much less attention to Goldfish can grow to nearly 23
color with deep bodies and unre- color and shape, as feeder fish; inches (58 cm) long and weigh 6
markable fins. It is believed that goldfish are also produced as bait. pounds (2.7 kg) or more. They can
the koi and goldfish varieties we There are too many varieties to live 30 years or more. Common
recognize today originated with describe in this profile; however, carp can grow to more than 4 feet
the breeding of uncommon gold- many books are dedicated to the (122 cm) long and weigh 80
en-colored carp in China 1,000 to topic. pounds (36 kg). Common carp
2,000 years ago. This early selec- have been known to live at least
tive breeding eventually led to the 50 years.
production of more than 100 vari-
Taxonomy
eties of koi and goldfish. Goldfish, Carassius auratus Marketing and economics
“Fancy” varieties exhibit body (Linnaeus 1758), and common
parts in unusual shapes, positions carp, Cyprinus carpio (Linnaeus The marketing and production
or colors. For example, a goldfish 1758), are members of the family economics of koi and goldfish are
may have a cap on its head—a Cyprinidae, or minnow family. as varied as the different strains
variety called an Oranda—or Koi is an ornamental variety of of fish. At one extreme, feeder
large sacs under its eyes—a the common carp. Goldfish are goldfish are sold by the pound or
Bubble Eye goldfish. Koi and native to central Asia, China and truck load as bait and as feeder
goldfish may have various scale Japan. Common carp are native to fish for aquaria. At the other
patterns and color markings that Eurasia, particularly the rivers extreme, individual champion koi
range from solid black to blue, draining into the Aral, Black and may be sold around the world
red, yellow, orange, white, or any Caspian Seas. The ornamental koi and transported in private jets.
combination and pattern of these variety was developed in China. In the U.S., most goldfish produc-
colors. Fin number, size and shape Japan also has had a great deal of tion (by volume) is for bait and
also can be different from one influence on the development of feeders. Most ornamental goldfish
variety to another, especially in koi. Both species have been wide- produced in the U.S. are at the
ly introduced around the world middle to low end of the price
and the precise limits of their level (examples are Black Moors,
*University of Florida, Institute of Food native ranges are uncertain. Both Shibunkins, Fantails, Calicos,
and Agricultural Sciences, Department of species are found in many types Comets, etc.). The most expensive
Fisheries and Aquatic Sciences, Tropical of fresh water. Goldfish are most varieties (e.g., Orandas, Ryunkins,
Aquaculture Laboratory. common in small, vegetated lakes;Lionhead
Bubble eye
Common goldfish for bait Butterfly koi
Bubble Eyes) are primarily Earthen ponds are often used, production densities are the most
imported from China. However, especially for koi and for low- to challenging systems to manage.
an increasing number of U.S. pro- mid-value goldfish. Pond con-
ducers are specializing in exotic struction must be carefully Water quality
varieties that can sell for as much planned in consultation with the
as $5.00 per fish wholesale. appropriate agencies responsible Koi and goldfish are considered
for permitting. Pond management “hardy” fish because they can sur-
Most U.S. koi production also has vive in poor water quality.
focused on the wholesale, large- concerns include managing dis-
solved oxygen and phytoplankton However, for optimal growth,
volume, inexpensive level. appearance, reproduction and
However, with the growing inter- blooms, managing aquatic plants,
controlling disease vectors such as health, maintaining good water
est in expensive outdoor garden quality is essential. Unlike most
ponds, more specialty producers snails, and controlling or exclud-
ing predators. Aeration can make other ornamental fish, which are
are raising fish that sell for hun- tropical, koi and goldfish are tem-
dreds of dollars each. As the pond management easier and
increase production. perate species. Their optimum
prices of goldfish and koi temperature range is about 65 to
increase, the size of the market Tank culture systems may be 75 °F (18 to 24 °C), although they
decreases, so most of the business flow-through or recirculating sys- can survive at temperatures as low
is at the lower end of the price tems. Flow-through tanks have a as 32 °F (0 °C) and as high as 95 °F
range. constant flow of new water. This (35 °C), especially if the tempera-
As in all of aquaculture, the key to flow dilutes and flushes fish ture change is gradual (seasonal).
success is to thoroughly investi- wastes from the system. The water Temperatures outside the optimal
gate the market before getting source is usually well water, but range may suppress the fishes’
into production, so that you surface water is sometimes avail- immune systems and cause
understand when buyers want able. Recirculating systems reuse decreased feeding and growth.
fish, how many they want, and water, filtering it to remove parti-
cles and fish waste products such Oxygen level should be at least 5
how much they will pay for them. mg/L, though koi and goldfish
Reports of someone paying as ammonia before returning it to
the tanks. Some systems also use will tolerate much lower dissolved
$10,000 for an individual champi- oxygen for short periods. Un-ion-
on koi do not translate into a mar- ultraviolet sterilizers, chemical fil-
ters and pure oxygen to increase ized ammonia and nitrite levels
ket strategy. should be kept below 0.05 mg/L.
production. Flow-through systems
are usually cheaper to build and The pH should be kept as close to
Culture systems operate than recirculating systems. 7 (neutral) as possible, though koi
Goldfish and koi are cultured in However, recirculating systems and goldfish may tolerate a pH
ponds, flow-through tanks, and use far less water and make it eas- between 5 and 9.
recirculating systems. The man- ier to maintain temperature and
agement of these systems is very administer disease treatments.
different; so are the costs and Recirculating systems with high
intensity of production.Koi
Ryunkin
Oranda Telescope
Brood stock offspring with a wide variety of released. The eggs are adhesive
characteristics, so producers who and under natural conditions they
Although koi and goldfish want high-quality brood stock are broadcast in grass and other
become sexually mature at 1 year should select breeders very care- vegetation along the water’s edge.
of age, fish used for commercial fully. Because of this, producers often
brood stock are usually at least 2 use spawning mats in koi and
years old. The larger the female, Goldfish genetics and brood stock
selection are even more complicat- goldfish culture. Spawning mats
the more eggs she will produce. are placed around the edges of
Also, some of the more elaborate ed because of the large number of
strains and varieties available. culture ponds or tanks. When
characteristics of exotic varieties spawning is completed the mats
do not fully express themselves Goldfish brood fish should be
selected for color, body shape, are moved to another pond or
until fish have reached a certain tank where the eggs are hatched.
age or size. absence or presence of dorsal fins,
single or multiple caudal fins, eye Spawning most often occurs dur-
Brood fish should be carefully shape and orientation, and absence ing the early morning hours. Both
selected for certain traits such as or presence of head growths and koi and goldfish consume their
size, color, health and finnage. nostril folds. This diversity may be eggs after spawning, so brood fish
This publication is too brief to one reason U.S. production has and mats with eggs should be
describe all the different breeding focused on the common, less separated quickly.
practices used to create certain extravagant varieties. Many producers also induce
varieties, but suffice it to say that spawning so that all females and
the quality of the offspring is all males will spawn at the same
directly related to the quality o
Spawning
time. Spawning agents such as
the brood stock. Koi and goldfish generally spawn human chorionic gonadotropin
In koi, the most important charac- in the spring, although they can (HCG), carp pituitary extract
teristics to select for are color, be conditioned to spawn through- (CPE), and releasing hormones
body shape, finnage and scales. out the year if kept in the proper (LHRH and GnRH) are all effec-
Koi are typically viewed from environment. The fish spawn tive. Koi and goldfish females
above, so brood fish should be from February to May (depending injected with these agents at 68 °F
selected from this vantage point. on the location in the U.S.) when (20 °C) will ovulate within 12
The color should be vibrant and water temperature approaches hours. The standard dry method
distinct, with no bleeding 68 °F (20 °C). To reduce sponta- of mixing the eggs and sperm is
between colors in multi-colored neous breeding, male and female used (i.e., eggs and sperm are
fish. Champion koi brood fish fish should be separated until mixed in a bowl and then water is
command a very high price and time for spawning. added). However, because they
usually are accompanied by a During spawning, females will be are adhesive, eggs must be trans-
pedigree to demonstrate the puri- pursued and “bumped” by sever- ferred quickly to a spawning mat
ty of their blood lines. Common, al males in shallow water. Several or some other flat surface to keep
inexpensive koi will produce males fertilize the eggs as they are them from clumping. Eggs can betreated with a solution of 4 grams cost of purchasing them may Goldfish bred to have multiple
of salt and 3 grams of urea per exceed the benefits. caudal fins or no dorsal fin can be
liter of water, which allows fertil- In pond culture, some feed is eaten culled very early on, but most
ization and “water hardening” by the fish and some serves as fer- other varieties (especially those
without activating the adhesive tilizer for the pond, helping to pro- dependent on color) must grow
layer. This procedure can be fol- duce natural foods such as algae, for several months before their
lowed by a 10- to 20-second rinse zooplankton and insects. Such nat- true appearance can be known.
in a solution of 0.5 grams of tan- ural foods can be very important Grading for size is done both
nic acid per liter of water, which to the nutrition of goldfish and mechanically—using grader
effectively eliminates the adhe- koi. Therefore, pond feeds often boxes—and by hand. Grading and
siveness. These eggs can then be are not complete diets (providing culling for appearance are done
hatched in upwelling jars. all the nutritional needs of fish) manually; this labor is a signifi-
Eggs hatch within 2 to 9 days and may cost much less than com- cant cost of production and exper-
depending on temperature. They plete feeds. In tank culture, com- tise in grading and culling orna-
hatch in 46 to 54 hours at 84 °F plete feeds must be used. mental fish takes time to develop.
and in 5 to 7 days at 70 to 75 °F. In systems producing the most
Because the cost of feed is a sig- expensive varieties, as many as 90
The larva has a yolk sac but nificant percentage of the total
begins to take feed on the second percent of the fish may be deemed
production cost, feed should be unmarketable.
or third day post-hatch. Koi and stored carefully to keep it fresh.
goldfish are relatively large when Heat and humidity rapidly
they first start feeding and will degrade feeds, so an air-condi-
Disease
immediately accept Artemia nau- tioned room or building is best for Koi and goldfish are susceptible to
plii or other foods 200 to 300 storage. In old feeds, the levels of many infectious (parasitic, bacteri-
micrometers in size. In large-scale vitamins (especially vitamin C) al, viral and fungal) and noninfec-
production, eggs on mats or in may be reduced and the lipids tious (environmental, nutritional
hatching jars are hatched indoors (fats) may be rancid. Never give and genetic) diseases. Poor envi-
and the fry transferred to fertil- moldy feeds to fish; molds may ronmental conditions and nutri-
ized ponds where natural foods produce toxins that can harm fish. tion can weaken their immune
(such as plankton) are available. systems and make them more sus-
Growout ceptible to disease.
Feeding
The market will determine the Goldfish and koi are especially
Goldfish and koi are omnivorous proper time for harvesting koi and prone to anchor worm (Lernaea),
and can be grown on various nat- goldfish. If fish are being pro- fish louse (Argulus), and mono-
ural and prepared feeds. Most duced as small feeders or bait, genetic trematodes (Dactylogyrus
producers use a standard 25 to they may reach market size in as and Gyrodactylus), as well as many
32% protein diet throughout the little as 3 to 4 months. Many orna- protozoan parasites such as Ich,
growout period. The particle size mentals can take a full year to get Trichodina and Chilodonella. Fish
should be increased from a fine to market size or quality. The deep are more vulnerable to parasites
meal up to about a 1/4 -inch pellet red color of some koi can take when water quality is poor.
as fish grow. Color is not a major more than a year to fully develop. Anchor worm and fish lice are vis-
factor in fish produced for feed- Orandas, Lionheads and Pompons ible to the naked eye and can be
ers, bait and inexpensive orna- also need more time for develop- identified easily. The presence of
mentals. However, color is critical ment of the characteristic head or monogenes and protozoans must
in more expensive ornamental nostril growths. This potential be confirmed by microscopic
fish. Like most fish, koi and gold- delay in return emphasizes the examination. Chemical treatments
fish will have better coloration need for producers to analyze the may be necessary to treat each of
when fed a diet with lots of pig- markets they wish to enter before these parasites, although improv-
ments. The koi and goldfish diets developing their business plans. ing environmental conditions is
that are designed to enhance the also important in decreasing the
coloration of extremely expensive numbers of pathogens and
fish are among the most expen-
Grading and culling improving fish health.
sive feeds used in aquaculture. Ornamental goldfish and koi are “Goldfish ulcer disease” or “koi
Goldfish and common carp lack often sold as individuals, so grad- ulcer disease,” commonly caused
true stomachs, so they benefit ing and culling are very impor- by the bacterium Aeromonas
from multiple feedings each day. tant. Size, color (and pattern), fins salmonicida, can cause open sores
Using automatic feeders will and body shape all help determine and may kill up to 50 percent of
reduce labor costs, but the capitol a variety and the price a fish will the fish population. The disease is
bring.most prevalent when temperatures diagnosed. If SVC is confirmed, Axelrod, H. R., E. Balon, R. C.
range from 55 to 75 °F (13 to 24 °C) the facility will be quarantined Hoffman, S. Rothbard and G.
and when fish have recently while it is determined how and to Wohlfarth. 1996. The com-
spawned or been handled. Over- what extent depopulation, clean- pletely illustrated guide to koi
crowding also helps spread the dis- ing and disinfecting will be for your pond. TFH
ease because of fish-to-fish contact required. Publications, Inc., Neptune
and poor water quality. If this or KHV is not a reportable disease. City, New Jersey.
any other bacterial disease is sus- However, it can kill many—or Davis, J. T. 1986. Baitfish. Pages
pected, fish should be submitted to even all—of the fish in a facility. If 149-158 in R. R. Stickney, edi-
a fish health diagnostician whenev- it is confirmed, the facility should tor. Culture of nonsalmonid
er possible. Only a diagnostician be depopulated, cleaned and dis- freshwater fishes. CRC Press,
can confirm any bacterial diseases infected as quickly as possible. Boca Raton, Florida.
that are present because other
infections may have similar symp- Fish that survive KHV or SVC Geran, J. 1992. The proper care of
toms. Fish also should be tested for infection may be carriers of the goldfish. TFH Publications,
antibiotic sensitivities so that the virus. Fish suspected of having Inc., Neptune City, New
appropriate treatment can be deter- either disease should be submitted Jersey.
mined. as soon as possible for laboratory Hartman, K. H., R. P. E. Yanong,
diagnosis. B. D. Petty, R. Francis-Floyd
Two viral diseases—koi herpes
virus (KHV) and spring viremia of and A. C. Riggs. 2004. Koi
Summary herpes virus (KHV) disease.
carp (SVC)—are of particular con-
cern. KHV affects only koi, while Goldfish and koi have been pro- EDIS Fact Sheet VM-149.
SVC affects both koi and goldfish. duced in captivity for a very long University of Florida, Institute
Both viruses are highly contagious time. They trace their lineage back of Food and Agricultural
and can cause significant mortality. to hardy, temperate water fish in Sciences, Gainesville, Florida.
Fish infected with these viruses the carp family. Production in the Huet, M. 1972.Textbook of fish
often have external parasites and U.S. is focused on bait feeder fish culture: breeding and cultiva-
bacterial infections also, which can and common, less expensive vari- tion of fish. Fish Farming
mask the presence of viruses. KHV eties that have a high volume in Books Ltd., Farnham,
occurs most often when water tem- the trade. However, there is grow- England.
perature is 64 to 81 °F (18 to 27 °C). ing interest in producing (and a Lochmann, R. and H. Phillips.
SVC is more common when water growing market for) the fancy 2001. Nutrition and feeding of
is 41 to 64 °F (5 to 18 °C). Young strains from which international baitfish. Publication number
fish are more susceptible to these champion individuals may be ETB256. Cooperative
diseases than mature fish, though worth thousands of dollars. The Extension Program,
all ages can be affected. Fish with global trade in koi and goldfish is University of Arkansas at
KHV may be lethargic, swim close complex, so potential producers Pine Bluff.
to the surface, and exhibit breath- should spend considerable time
ing distress and erratic behavior. investigating the market before Lochman, R., N. Stone and E.
They may have dead tissue in their investing in production. Park. 2002. Baitfish: feeds and
gills and sunken eyes Fish infected feeding practices. SRAC
with SVC are often lethargic, stay References and Publication 121.
near the bottom of the pond or recommended reading Penzes, B. and I. Tolg. 1983.
tank, and swim awkwardly. They Goldfish and ornamental
also may have exophthalmia (“pop Andrews, D. 1987. Fishkeeper’s carp: a comprehensive guide
eye”), pinpoint bleeding on the guide to fancy goldfishes. to the care of both new and
skin, a bloated abdomen, and Tetra Press, Morris City, New popular varieties. Eugen
bloody mucus coming from the Jersey. Ulmer GmbH & Co.,
vent. It is very important to Axelrod, H. R. 1992. Koi varieties: Stuttgart, Germany.
remember that all of the symptoms Japanese colored carp— Petty, B. D., A. C. Riggs, R.
of KHV and SVC can be caused by nishikigoi. TFH Publications, Klinger, R. Yanong and R.
other diseases or water quality Inc., Neptune City, New Francis-Floyd. 2002. Spring
problems, so both diseases must be Jersey. viremia of carp. EDIS Fact
confirmed by a laboratory diagnos- Sheet VM-142. University of
tician skilled in identifying viral Florida, Institute of Food and
diseases. Agricultural Sciences,
SVC is a reportable disease; federal Gainesville, Florida.
authorities must be notified if it isSealey, W. M., D. E. Barziza, J. T. Stone, N., E. Park, L. Dorman and Wedemeyer, G. A., editor. 2001.
Davis and D. M. Gatlin III. H. Thomforde. 1997. Baitfish Fish hatchery management.
1998. Dietary protein and culture in Arkansas: golden 2nd edition. American Fisheries
lipid requirements of golden shiners, goldfish and fathead Society, Bethesda, Maryland.
shiners and goldfish. SRAC minnows. Publication MP 386. Yoshiichi, M. and H. R. Axelrod.
Publication 124. Cooperative Extension 1991. Goldfish guide. 3rd edi-
Smart, J. and J. H. Bundell. 1996. Program, University of tion. TFH Publications, Inc.,
Goldfish breeding and genet- Arkansas at Pine Bluff. Neptune City, New Jersey.
ics. TFH Publications, Inc., Tamadachi, M. 1990. The cult of
Neptune City, New Jersey. the koi. 2nd edition. TFH
Publications, Inc., Neptune
City, New Jersey.
SRAC fact sheets are reviewed annually by the Publications, Videos and Computer Software Steering
Committee. Fact sheets are revised as new knowledge becomes available. Fact sheets that have not
been revised are considered to reflect the current state of knowledge.
The work reported in this publication was supported in part by the Southern Regional Aquaculture Center through
Grant No. 2002-38500-11805 from the United States Department of Agriculture, Cooperative State Research,
Education, and Extension Service.You can also read
