Koi & Goldfish – The Same
Or Different?

Have you ever wondered if there is a such thing as a koi goldfish? Is it one kind of fish or two different kinds?

Well, even though they are both descended from carp, they ARE different.

Koi were bred and developed in Japan, and goldfish were bred and developed in China.  Aside from their origins they have other differences (and similarities) as well.

If you aren’t sure whether you should have koi, goldfish, or both, consider the needs of each.

A major consideration is the size of your pond. Koi need much more room than goldfish for a few reasons.

The first, and one of the primary differences, is that koi will grow to be larger than goldfish.  Along with this is the fact that even though they are generally longer-lived than goldfish are, they need better water quality to survive and thrive.

Goldfish can live in a smaller pond with very little care. Koi should have a minimum 1000 gallon pond, and you need to be careful that you don’t overpopulate it at the beginning when the koi are younger and smaller in size! Overpopulation is a primary cause of poor water quality.

As far as other physical differences, koi have a more tubular shape than goldfish do and they sport a wider variety of colors and patterns. They also can be distinguished from goldfish by the barbels, which look like whiskers, on each side of their mouth.

There are some fancy varieties of goldfish as well, but these varieties don’t usually do well in outdoor ponds. The plainer, slender bodied varieties are hardier and better suited to pond life.

Koi and goldfish can live together very well. So, if you think you’d like both there’s no reason not to have them. They can even interbreed, although their offspring will be sterile.

It is a good idea to gather as much information as you can about koi and pond care since koi are a bit higher maintenance than goldfish. And who knows…maybe you could call their occasional offspring koi goldfish!

Although it began in Japan, today Koi breeding takes place all over the world. Many people enjoy Koi ponds and some may even consider trying their hand at Koi breeding.

With that in mind let’s get down to the basics!

The first thing you need to do is to determine the sex of your Koi. This is impossible to do until the fish becomes sexually mature which usually hapens when it gets to 10 inches or longer. Even sexually mature fish can be tricky to sex but in general a male Koi will be less plump than a female Koi because a mature female has filled ovaries that expand her body.

The sexually mature male Koi typically looks more slim and streamlined and often has larger and somewhat more pointed pectoral fins than the female. There are some exceptions to these general rules and it is possible to have a scrawny female or fat male Koi fish.

When Koi breeding season begins the male Koi will develop two white spots on his head and on the first rays of his pectoral fins. The breeding tubercles will look like small white elevated spots and can be hard to recognize. The Koi breeder sometimes becomes alarmed and treats their fish for itch when they notice the small white spots, but with practice soon learns to recognize them.

If you keep your Koi in an outdoor pond they will start to spawn in late spring and early summer as the water temperature begins to rise. A water temperature around 20 degrees Celcius or 68 degrees Fahrenheit is ideal to stimulate Koi breeding.

If you keep a lot of Koi together a so-called flock spawning will occur. A flock spawning will give you an abundance of healthy offspring but breeders try to avoid them because these fish often display less desirable colorations.

Thus, during professional Koi breeding, the fish keeper will select desirable parent fish and place them in their own pond. You will need one female and two to three males for a successful Koi breeding.

If you don’t want to dig a new pond especially for Koi breeding you can use a children’s swimming pool. To increase the chances of spawning you can change the water frequently and lower the water temperature somewhat.

Adult Koi eat live foods such as worms and flies and parents won’t hesitate to eat eggs as well as free swimming offspring in their own pond! During professional Koi breeding when a large survival rate is important the eggs are best placed in their own ponds.

Collecting the eggs will be difficult if you let your fish deposit eggs all over the pond. Most breeders therefore use spawning mops. A spawning mop can be made from frayed nylon ropes or pieces of cotton string that are placed on the surface of the pond.

The breeding fish see the mops as floating plants and will most likely choose them as a breeding site.

During the Koi breeding you will eventually notice that the males are chasing the female. This behavior usually goes on for several days before any eggs are released.

When the females deposit their eggs at the spawning mop the males will immediately go over and fertilize them. The spawning mops can then be removed and placed in a fry raising pond.

As you can see, though it takes some preparation and attention it is not all that difficult to perform a successful Koi breeding.

Alan Deacon
KoiCareBasics.com