The goldfish is a classic in outdoor ponds. A member of the carp family, this fish is easy to live with in temperate regions since it can withstand progressive temperature changes of a significant amplitude.
The goldfish originates from China where it has been regularly and selectively bred for over a thousand years. Originally, the goldfish was a rather dull Asian carp which gained in color through crossbreeding and hybridization.
From the Cyprinidae family, it is a close relative of the carp while presenting much more restricted measurements what destines it particularly to small outdoor ponds and indoor aquariums.
Like the carp, the goldfish comes in a multitude of varieties. The most common goldfish have a stocky and compact body that is entirely orange-red. This variety usually reaches a maximum of 25 cm in aquariums but can reach up to 40 cm in outdoor ponds.
All these fish have the characteristic to reproduce perfectly and easily in outdoor ponds, less easily in aquariums because of the promiscuity and the voracity of the adults.
Very resistant to temperature changes, goldfish can easily withstand a winter outside at -10°C as long as the temperature drop is not too fast. In the same way, it can adapt to strong heat as long as the rise in temperature is gradual.
This is not the case for the goldfish variety known as "sail tails" or comets, which do not tolerate large temperature changes outside!
Many other varieties have been created by man over the centuries, some of which are only red in name! The most eccentric ones are the lionhead goldfish which are distinguished from the others by protuberances on the top of the head, the telescopic goldfish with exorbitant eyes, the shubukin with very long dorsal and caudal fins, etc. The classic colors are red-orange but many species mix several colors: white and red, golden yellow and white, intense black...
The longevity of goldfish is generally 5 to 10 years on average in aquariums while in outdoor ponds, they can happily exceed 15 years very commonly. Goldfish grow throughout their lives.
