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Goldfish: The Goldfish (Carassius auratus)
was one of the earliest fish to be domesticated, and is still one of
the most commonly kept aquarium fish. A relatively small member of
the carp family (which also includes the koi carp and the crucian
carp), the goldfish is a domesticated version of a
dark-gray/olive/brown carp native to east Asia (first domesticated
in China) that was introduced to Europe in the late
17th century. The mutation that gave rise to the goldfish is also
known from other cyprinid species, such as common carp and tench.
Most Common Types of
Goldfish:
Comets, which have a long tail and skinny
body. Comets were developed in the United States.
Fantails, that are shaped kind of like a fat egg. They have
double anal and caudal fins (those are the bottom and tail fins).
Veiltails have long flowing fins, and are very popular. Some
of them have telescope eyes that stick out on each side of their
head.
Shubunkins have a big caudal fin (that's the tail fin), and
come in many colors. They are very popular for ponds.
Black Moors are my mom's favorite. They are all black, have
telescope eyes, and veiltails. In Britain they breed them specially
for competition.
Lionheads have a bumpy growth on their head that kind of
looks like a lion's mane. They don't have a dorsal (top) fin, and a
double caudal fin. The Oranda is a Lionhead with a veiltail and a
dorsal fin.
Bubble-eyes are one of the oddest goldfish. They have large
sacs below the eye that look like someone blew their bubblegum and
stuck it under their eyes. Like Lionheads, they don't have a dorsal
fin and can't swim too well.
Goldfish may grow to a maximum length of 23 inches (59 cm) and a
maximum weight of 9.9 pounds (4.5 kg), although this is rare; most
individual goldfish grow to under half this size. In optimal
conditions, goldfish may live more than 20 years (the world record
is 49 years); however, most household goldfish generally only live
six to eight years.
History
During the Tang
Dynasty, it was popular to raise carp in ponds. As the result of a
dominant genetic mutation, one of these carp displayed "gold"
(actually yellowish orange) rather than silver coloration. People
began to breed the gold variety instead of the silver variety, and
began to display them in small containers. The fish were not kept in
the containers permanently, but would be kept in a larger body of
water, such as a pond, and only for special occasions at which
guests were expected would they be moved to the smaller container.
A crucian carp carrying a mutation for yellow
pigment. Some of the first goldfish may have looked like this.In
1162, the empress of the Song Dynasty ordered the building of a pond
to collect the red and gold variety of those carp. By this time,
people outside the royal family were forbidden to keep goldfish of
the gold (yellow) variety, yellow being the royal color. This
probably is the reason why there are more orange goldfish than
yellow goldfish, even though the latter are genetically easier to
breed.
As time passed, more mutations occurred, producing
new color variations, and fancier varieties of goldfish were
developed. The occurrence of other colors was first recorded in
1276. The first occurrence of fancy tailed goldfish was recorded in
the Ming dynasty. In 1502, goldfish were introduced to Japan, where
the Ryukin and Tosakin varieties were developed.
In 1611,
goldfish were introduced to Portugal and from there to other parts
of Europe. Goldfish were first introduced to North America in 1874
and quickly became popular in the United States.
Varieties of
domesticated goldfish
Selective breeding over centuries has
produced several color variations, some of them far removed from the
"golden" color of the originally domesticated fish. There are also
different body shapes, fin and eye configurations. Some extreme
versions of the goldfish do need to be kept in an aquarium ° they
are much less hardy than varieties closer to the "wild" original.
However, some variations are hardier, such as the Shubunkin. The
main varieties are:
Common Names: Black Moor, Bubble
Eye, Celestial Eye, Comet, Fantail, Lionhead, Oranda, Pearlscale,
Pompom, Ryukin, Shubunkin, Telescope Eye, Ranchu, Panda Moor,
Veiltail
Chinese Goldfish classification
In Chinese
goldfish keeping, goldfish are classified into 4 main types, which
are not commonly used in the west.
Dragon Eye - Goldfish with
extended eyes, e.g. Black Moor, Bubble Eye, and Telescope Eye
Egg - Goldfish without a dorsal fin. e.g. Lionhead (note that a
Bubble Eye without a dorsal fin belongs to this group)
Wen -
Goldfish with dorsal fin and a fancy tail. e.g. Veiltail ("Wen" is
also the name of the characteristic headgrowth on such strains as
Oranda and Lionhead)
Ce (may also be called "grass") - Goldfish
without anything fancy. This is the type that is usually used in
Japanese carnivals, especially for "goldfish scoops".
Jikin and
Wakin - Goldfish with double tails, but with the body shapes of
comets.
Goldfish in ponds
Goldfish are popular pond fish,
since they are small, inexpensive, colourful, and very hardy. In a
pond, they may even survive if brief periods of ice form on the
surface, as long as there is enough oxygen remaining in the water
and the pond does not freeze solid.
Common goldfish, London
and Bristol shubunkins, Jikin, Wakin, comet and sometimes fantail
can be kept in a pond all year round in temperate and subtropical
climates. Moor, veiltail, oranda and lionhead are only safe in the
summer.
Goldfish pond; Small to large ponds are fine though
the depth should be at least 80 cm (30 in) to avoid freezing. During
winter, goldfish will become sluggish, stop eating, and often stay
on the bottom of the tank. This is completely normal; they will
become active again in the spring. A filter is important to clear
waste and keep the pond clean. Plants are essential as they act as
part of the filtration system, as well as a food source for the
fish. Plants are furthermore beneficial since they raise oxygen
levels in the water.
Compatible fish include rudd, tench,
orfe and koi, but the latter will require specialized care. Ramshorn
snails are helpful by eating any algae that grows in the pond. It is
of great importance to introduce fish that will consume excess
goldfish eggs in the pond, such as orfe. Without some form of
population control, goldfish ponds can easily become overstocked.
Koi may also interbreed to produce a sterile new
fish.
Goldfish in aquaria
The goldfish is usually
classified as a coldwater fish, and it can live in an unheated
aquarium. Like most carp, goldfish produce a large amount of waste
both in their feces and through their gills, releasing harmful
chemicals into the water. This also happens because goldfish cannot
digest an excess of proteins, unlike most tropical fish. Build-up of this waste to toxic levels can occur in a
relatively short period of time, which is often the cause of a
fish's sudden death. It may be the amount of water surface area, not
the water volume, that decides how many goldfish may live in a
container, because this determines how much oxygen diffuses and
dissolves from the air into the water; one square foot of water
surface area for every inch of goldfish length (370 cm°/cm). If the
water is being further aerated by way of water pump, filter or
fountain, more goldfish may be kept in the container.
Goldfish aquarium; Goldfish may be coldwater fish,
but this does not mean they can tolerate rapid changes in
temperature. The sudden shift in temperature that comes at night,
for example in an office building where a goldfish might be kept in
a small office tank, could kill them, especially in winter.
Conversely, temperatures over 25 °C can be extremely damaging for
goldfish (this is the main reason why they shouldn't be kept in
tropical tanks).
The popular image of a
goldfish in a small fishbowl is an enduring one. Unfortunately, the
risk of stunting, deoxygenation, ammonia/nitrite poisoning caused by
such a small environment means that this is hardly a suitable home
for any species of fish, and some countries have banned the sale of
bowls of that type under animal rights legislation.
The
supposed reputation of goldfish dying quickly is often due to poor
care amongst uninformed buyers looking for a "cheap" pet. The true lifespan of a well-cared-for goldfish in captivity
can extend beyond 10 years.
Fancy goldfish are unlikely to
survive for long in the wild as they are handicapped by their bright
fin colors; however it is not beyond the bounds of possibility that
such a fish, especially the more hardy varieties such as the
Shubunkin, can survive long enough to breed with its wild cousins.
Common and comet goldfish can survive, and even thrive, in any
climate in which a pond for them can be created. Introduction of
wild goldfish can cause problems for native species. Within three
breeding generations the vast majority of the goldfish spawn will
have reverted to their natural olive color. Since they are carp,
goldfish are also capable of breeding with certain other species of
carp and creating hybrid species.
Research
by Dr. Yoshiichi Matsui, a professor of fish culture at Kinki
University in Japan, suggests that there are subtle differences
which demonstrate that while the crucian carp is the ancestor of the
goldfish, they have sufficiently diverged to be considered separate
species.
Feeding
Common flake fish foodLike most fish,
goldfish are opportunistic feeders and do not stop eating of their
own accord. When an excess of food is offered, they will produce
more waste and feces, partly due to incomplete digestion of protein.
Overfed fish can sometimes be recognized by feces trailing from
their cloaca. Goldfish need only be fed as much food as they can
consume in three to four minutes, and no more than twice a day.
Extreme overfeeding can be fatal, typically by bursting of the
intestines. This happens most often with selectively bred goldfish,
which have a convoluted intestinal tract as opposed to a straight
one in common goldfish. Novice fishkeepers who have newly purchased
ruykin, fantail, oranda, lionhead or other "fancy" goldfish will
need to watch their fish carefully for a few days, as it is
important to know how much the goldfish will eat in a few minutes of
time.
Special goldfish food has a lower protein and higher
carbohydrate content. It is sold in two consistencies - flakes that
float at the top of the aquarium, and pellets that sink slowly to
the bottom.
Goldfish enthusiasts will supplement this diet
with shelled peas (with outer skins removed), blanched green leafy
vegetables, and bloodworms. Young goldfish also benefit from the
addition of brine shrimp to their diet.
Behavior
Behavior can vary widely both because goldfish are housed in a
variety of environments, and because their behavior can be
conditioned by their owners. A common misconception that goldfish
only have a three second memory has been proven completely false.
Scientific
studies done on the matter have shown that goldfish have strong
associative learning abilities, as well as social learning skills.
In addition, their strong visual acuity allows them to distinguish
between different humans. It is quite possible that owners will
notice the fish react favorably to them (swimming to the front of
the glass, swimming rapidly around the tank, and going to the
surface mouthing for food) while hiding when other people approach
the tank. Over time, goldfish should learn to associate their owners
and other humans with food, often "begging" for food whenever their
owners approach.
Goldfish also display a range of social
behaviors. When new fish are introduced to the tank, aggressive
social behaviors may sometimes be seen, such as chasing the new
fish, or fin nipping. These usually stop within a few days. Fish
that have been living together are often seen displaying schooling
behavior, as well as displaying the same types of feeding behaviors.
Goldfish may display similar behaviors when responding to their
reflections in a mirror.
Goldfish that have constant visual
contact with humans also seem to stop associating them as a threat.
After being kept in a tank for several weeks, it becomes possible to
"pet" a goldfish on the head, feed it by hand, or even cup a hand
around it without it reacting in a frightened manner. Some goldfish
have been trained to swim through mazes, push a ball through a hoop,
or even swim in a synchronized routine by their owners.
Goldfish have behaviors, both as groups and as
individuals that stem from native carp behavior. They are a
generalist species with varied feeding, breeding, and predators
avoidance behaviours that contribute to their success in the
environment. As fish they can be described as "friendly" towards
each other, very rarely will a goldfish harm another goldfish, nor
do the males harm the females during breeding. The only real threat
that goldfish present to each other is in food competition. Commons,
comets, and other faster varieties can easily eat all the food
during a feeding before fancy varieties can reach it. This can be a
problem that leads to stunted growth or possible starvation of
fancier varieties when they are kept in a bond with their
single-tailed brethren. As a result, when mixing breeds in an
aquarium environment, care should be taken to combine only breeds
with similar body type and swim characteristics.
Native
environment
Goldfish natively live in ponds, and other slow or
still moving bodies of water in depths up to 20 m (65 ft). Their
native climate is subtropical to tropical and they live in
freshwater with a pH of 6.0°8.0, a water hardness of 5.0°19.0 dGH,
and a temperature range of 40 to 106 °F (4 to 41 °C) although they
will not survive long at the higher temperatures. They are
considered ill-suited even to live in a heated tropical fish tank,
as they are used to the greater amount of oxygen in unheated tanks,
and some believe that the heat burns them. However, goldfish have
been observed living for centuries in outdoor ponds in which the
temperature often spikes above 86 °F (30 °C). When found in nature,
the goldfish are actually an olive green color.
In the wild,
the diet consists of crustaceans, insects, and various plant
matter.
While it is true that goldfish can survive in a
fairly wide temperature range, the optimal range for indoor fish is
68 to 75 °F (20 to 23 °C). Pet goldfish, as with many other fish,
will usually eat more food than it needs if given, which can lead to
fatal intestinal blockage. They are omnivorous and do best with a
wide variety of fresh vegetables and fruit to supplement a flake or
pellet diet staple.
Sudden changes in water temperature can
be fatal to any fish, including the goldfish. When transferring a
store-bought goldfish to a pond or a tank, the temperature in the
storage container should be equalized by leaving it in the
destination container for at least 20 minutes before releasing the
goldfish. In addition, some temperature changes might simply be too
great for even the hardy goldfish to adjust to. For example, buying
a goldfish in a store, where the water might be 70 °F (approximately
21 °C), and hoping to release it into your garden pond at 40 °F (4
°C) will probably result in the death of the goldfish, even if you
use the slow immersion method just described. A goldfish will need a
lot more time, perhaps days or weeks, to adjust to such a different
temperature.
Because goldfish like to eat live plants, their
presence in an aquarium can be quite a problem. Only a few of the
aquarium plant species can survive in a tank with goldfish, for
example Cryptocoryne and Anubias species, but they require special
attention so that they are not uprooted. Fake plants are often more
durable, but the plant branches can often irritate or harm a fish if
it comes in contact with them.
Breeding
Goldfish, like all
cyprinids, lay eggs. They produce adhesive eggs that attach to
aquatic vegetation. The eggs hatch within 48 to 72 hours, releasing
fry large enough to be described as appearing like "an eyelash with
two eyeballs". Within a week or so, the fry begin to look more like
a goldfish in shape, although it can take as much as a year before
they develop a mature goldfish color; until then they are a metallic
brown like their wild ancestors. In their first weeks of existence,
the fry grow remarkably fast - an adaptation born of the high risk
of getting devoured by the adult goldfish (or other fish and
insects) in their environment.
Goldfish can only grow to
sexual maturity if given enough water and the right nutrition.
However if kept well, they may breed indoors. Breeding usually
happens after a significant change in temperature, often in spring.
Eggs should then be separated into another tank, as the parents will
likely eat any of their young that they happen upon. Dense plants
such as Cabomba or Elodea or a spawning mop are used to catch the
eggs.
Most goldfish can and will breed if left to themselves,
particularly in pond settings. Males chase the females around,
bumping and nudging them in order to prompt the females to release
her eggs, which the males then fertilize. Due to the strange shapes
of some extreme modern bred goldfish, certain types can no longer
breed among themselves. In these cases, a method of artificial
breeding is used called "hand stripping". This method keeps the
breed going, but can be dangerous and harmful to the fish if not
done correctly.
Mosquito control
Like some other
popular aquarium fish, such as the guppy, goldfish and other carp
are frequently added to stagnant bodies of water in order to reduce
the mosquito populations in some parts of the world, especially to
prevent the spread of West Nile Virus, which relies on mosquitoes to
migrate. However, the introduction of goldfish has often had
negative consequences for local ecosystems.
Edibility and
cruelty
Although edible, goldfish are rarely eaten. A fad among
American college students for many years was swallowing goldfish as
a stunt and as an initiation process for fraternities. The first
recorded instance was in 1939 at Harvard University. The practice
gradually fell out of popularity over the course of several decades
and is no longer continued.
Goldfish being scooped up
In many
countries, the operators of carnivals and fairs commonly give
goldfish away in plastic bags as prizes for winning games. In the
United Kingdom, the government proposed banning this practice as
part of its Animal Welfare Bill, though this has since been
amended to only prevent goldfish being given as prizes to
unaccompanied minors. However, in Rome, Italy, the city passed a law
in late 2005, which banned the use of goldfish or other animals as
carnival prizes. Rome has also banned the keeping of goldfish in
"goldfish bowls", on the premise that it's cruel to the fish to live
in such a small, confined space.
Killing fish humanely
for human consumption or benign purposes (such as putting down an
ill fish) is still legal in most countries (provided that the fish
is not a protected fish caught in the wild, a fish in protected
reserves or in water where the person concerned has no right to
collect the fish). In the United Kingdom, it is illegal to sell live
fish (including goldfish) as "feeder fish" for consumption by other
animals.
Source: Columbia Encyclopedia, Sixth Edition,
Copyright (c) 2009.
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