Breeding goldfish in a pond

Goldfish were ‘discovered’ by mistake, when their brown ancestors were bred for food thousands of years ago in China. Now they are bred commercially across many continents to feed our eyes and our insatiable demand for glowing pond dwellers.

Related to the carp, the goldfish spawns like many other members of the carp family, carrying out a strategy that has been successful for many thousands of years.

Goldfish are gregarious creatures, swimming and feeding in small shoals. They also breed in a shoal, where the fish will reach breeding condition together and spawn spontaneously as a group.

What to look out for :

Contrary to what you may expect of such a successful fish, goldfish are very poor parents. They will readily consume their own eggs or those of a mate and even when the surviving eggs have hatched, fry are just as prone to being inadvertently cannibalised.

Fortunately, to improve the probability of a number of fry surviving all of the trials of early life, goldfish, – in true carp family style, will release thousands of eggs per fish.

Despite such odds against survival, the typical garden pond is capable of producing a good number of homebred goldfish.

How to breed goldfish in a garden pond:

There are only a few specific requirements to produce a successful goldfish spawn in a garden pond.

1. Suitable goldfish.

There are no prerequisites as to the quality or variety of goldfish that need to be considered before breeding. However, they will need to be sexually mature, (at least 2 years old and 6-8″ long), and it is advisable for males to outnumber females.

Males can be sexed by their sleeker bodies and longer more flamboyant finnage. Females are generally plumper and more rounded, especially as summer approaches.

2. Suitable pond.

Only healthy and well-fed goldfish will go on and spawn. A lightly stocked pond with well-filtered water and good water quality will improve the likelihood of a spawn.

Goldfish ‘flock spawn’ where the males appear to show aggression to the plump females, chasing them into the shallows and densely planted areas. The ripe females release pheromones which attracts the attentions of all the males in the pond, which in turn drive and chase each female (whether ripe or not) to expel their eggs.

Goldfish produce tiny adhesive eggs that are translucent. Upon their release they are fertilised by the sperm released by the chasing males and will stick to any hard surface, such as plants, pipework and pond lining.

3. Densely planted area.

To improve the chances of producing a number of goldfish fry, the pond should have an area that is densely planted. This will act as both a spawning material and a sheltered nursery for the developing fry.

Although fry should be fed a prepared fry diet, the densely planted areas will also provide minute food particles for the fry to graze on.

For many pondkeepers, it is the appearance of tiny olive brown fry in the warmer weedy margins that indicates that the fish have spawned. It is also common to wonder which fish have produced the tiny home-bred fry as you are sure there aren’t any brown parents in the pond.

In reality, the small brown fry are goldfish showing typical immature colouration, hinting again as to their ‘wild’ ancestry. (However, being brown at this vulnerable stage has its advantages of camouflage). Over the next few weeks as the fry develop into fingerlings, some may develop gold livery or retain the colouration of their cryptic ancestry.

And there you have it, a variety of homebred goldfish, produced in your own back garden.

Kill blanketweed and string algae.