The fancy ones are...well, fancy - still goldfish, but nothing like the real thing.
By Stephen M. Meyer
Q. I am thinking about breeding goldfish eventually, and I thought it might be fun to breed the original goldfish, rather than
the fancy varieties that are commonly sold. When I inquired at a local pet store they told me the "original goldfish" was
Cyprinos carpio. But a book I checked said that the original goldfish was Carassius auratus. Are these the same? Which is
the wild one? I also read that wild goldfish are actually brown. Is this true?
A. Carassius auratus is a domesticated form of a small wild carp (Carassius auratus gibelio) found in south China and
southeast Asia. It is a brownish colored fish with shiny scales. So although Carassius auratus is not the true "wild" goldfish
you seek, it is certainly as close to the original as you will come to it in this country.
Let's sort out our carp. Cyprinos carpio is a common wild carp. It is a large fish and is a cousin of Carassius auratus gibelio.
Koi — the large carp that the Japanese have bred to many beautiful colors — is the domesticated version.
So, back to goldfish. Carassius auratus gibelio produce large numbers of eggs per spawn. Depending on conditions, a
single female may deposit anywhere from 100,000 to 300,000 eggs onto aquatic vegetation. And they may spawn more
than once per season. Given such large numbers of progeny, random genetic variation produces a handful of fish with
unusually large numbers of yellow color cells, which produce the golden look.
In the wild, however, these brightly colored individuals are not long for this world. Their shiny reflection attracts predators
quickly, and they soon become a previous member of the food web. Therefore, the combination of their relative rarity in birth
and low odds of survival to maturity make it almost impossible that a male and female with very colorful characteristics will
Of course, the situation is quite different in goldfish breeding ponds. First, breeders carefully select the fish with the most
desirable color traits, finnage and so on. Second, they choose breeding pairs based on the strength and stability of those
characteristics. Third, they cull the resulting fry in a manner precisely opposite that taken by Mother Nature. The
normal-colored fish are tossed and the novel ones are kept, and protected from predation.
Wild goldfish are not really brown, but a deep green along their back and upper sides. A mixture of silver and yellow
coloration blends along the sides, which, when viewed from the side, can give a perception of brown. These animals can
achieve weights of more than a pound in the wild, and grow to well over a foot in length, with the tail adding another several
You should be able to have some inexpensive fun with wild goldfish "lookalikes" by picking up some feeder goldfish at a
local pet store. These are the random offspring of ordinary pet goldfish (or they may actually be culls from selective breeding
efforts). Choose individuals that are greenish-brown with silvery reflections along the sides.
As they mature you can let them randomly breed and continue the regression toward their wild ancestors. Have fun.
Moor Than Enough
Q. We have a calico fantail. Could this be a kind of moor? It looks like our other goldfish, which are all moors. Also, we have
a ton of spare moors. If you want any you can have some.
A. Thanks for the offer. I'm afraid all my tanks are occupied right now — and hopefully will stay that way for a good long while.
It is a really good idea to thin out the herd of fish before Mother Nature steps in to do it her way. Too many fish in too small a
space is a guaranteed disaster in the making. Sooner or later disease will thin out the residents of the tank.
If your moors are of modest quality a local pet store might be interested in taking some. They might give you cash or
merchandise in trade.
Maybe some of your friends would like to try their hands at fishkeeping. Why not offer some as giveaways? A local school
might be interested in taking a few moors to add a little life to its classrooms.
Could your calico be a moor in disguise? Well, in a sense. All goldfish are closely related. The varieties offered in pet stores
are specially bred for form and color. They can look very different, but they are really the same fish.
Calico fantails are a variety of goldfish distinct from moors. The body form, eyes and finnage may be similar, or near
identical. The primary difference is color. Moors are velvet black, whereas calico fantails are blue, black, red, metallic
flecked and so on.
Plain With Fancy?
Q. I've set up a 30-gallon tank to house some goldfish. I haven't quite decided what I want yet, but a salesperson at my local
pet store said to not mix feeder-type goldfish with fancy ones — no explanation given. Is there a reason to keep the two types
A. It's not that you can't keep regular and fancy goldfish in the same tank, but there are two reasons why goldfish hobbyists
do not recommend mixing feeder goldfish and show (fancy) goldfish. The first is that feeders tend to be fast, frisky
swimmers. They are built for swimming.
Fancy goldfish, in contrast, tend to be slow, ungainly, fat and not well equipped to compete for food. Thus, if you mix them in
the same tank, your feeders will get most of the food and grow rapidly, but your expensive fancy goldfish will barely get
enough to stay alive. That's the most important reason not to keep the two types together.
The second reason is that all goldfish are goldfish — meaning they can and will breed together regardless of their physical
appearance. The feeders are close approximations of wild goldfish (see the first question in this column for a detailed
explanation). The fancy goldfish are distant genetic strains.
If the two breed, the result will be a regression toward the characteristics of wild goldfish, which lack the color, form and
finnage that make fancy goldfish so special and so expensive. Moreover, because the feeders are far more vigorous than
fancy goldfish, there is a good chance that breeding will result in serious physical harm to the fancy goldfish. Goldfish
breeding tends to be a rough and tumble affair.
Goldfish in Ponds
Q. This summer I will be enlarging my garden pond so that it will be 7 feet long, 5 feet wide and 3 feet deep. I would like to
keep fancy goldfish. Because the pond will still really be a garden pond, it will not have a filter or aeration system. How many
fancy goldfish can I keep? Will they be able to overwinter in this pond?
A. Based on the measurements you intend to enlarge the pond to, I'd estimate that it will have a surface area about 24
square feet and a volume of 630 gallons, assuming it has an oval shape. Fancy goldfish vary considerably in size, so I can
only suggest a guideline.
Because the pond will not have either a filter or aeration system, I would not put more than 10 small- to medium-sized fancy
goldfish in it. But, of course, fish grow unless you purchase adults (very expensive with good-quality fancy goldfish). If the
fish are closer to 6 inches, I would put no more than three in the pond. While the fish are not particularly long, they have
large bodies and will create the biological load equivalent of many more smaller, slimmer fish.
Because your pond is a garden pond, I assume it will be well stocked with aquatic plants. This is very important when there
is no filter or aearion for a pond with fish in it. I would monitor ammonia levels very carefully during the first month.
Goldfish can overwinter in ponds in the Northeast, but only if the pond is at least 3 feet deep if, and only if: 1) the stocking
level is very low, as I have suggested; 2) the pond is absolutely clean of leaves and debris before it freezes over; and 3) the
fish are healthy and well fed going into the winter season. If you can keep a small hole open in the ice — using a de-icer, for
example — you can decrease the stress of overwintering on the fish.
Fancy goldfish are more sensitive to the cold than comets. I have kept comets outdoors and never lost one except under the
most severe winter conditions. Orandas tend to do fairly well also, but long-finned varieties often suffer from bacterial
infections in the very ends of their fins. I would not keep prized fish outdoors during the winter in the part of the country
where you live.