The breeding of goldfish

Can you remember the article we did about caring for goldfish? Our Veterinary Surgeon Dr. D. A. U. Samankumara of the Kirindiwela Animal Clinic, is back with us to tell you more about breeding goldfish.

Goldfish reach maturity in a fairly short time; males are capable of reproduction after one year, while females become mature after a year in a warm climate, or after two years in colder areas. In addition, they spawn once a year in a moderate climate.

Goldfish normally spawn actively when the water temperature reaches about 15-21 degrees Celsius. Goldfish do not form pair bonds. They are promiscuous breeders; any male will be with any female. Spawning usually begins at dawn and is completed in two or three hours. The eggs will be ejected to the water.

As the eggs fall into the water, they stick to the plants by a sticky thread. After a few minutes, the two fish separate. The number of eggs per female is above 2000-4000. However, a large female can lay as many as 10,000 eggs.

During spawning and immediately after, both fish greedily eat as many eggs as they can find. So, they should be removed from the pond or aquarium when spawning is over.

Fertility

Fertilised eggs are transparent and pale dirty yellowish in colour, while the whitish opaque coloured eggs are unfertilised. Fertilisation depends on the sex ratio, age of breeders, weight of breeders, number of eggs and environmental factors such as temperature, and the water's pH number.

During this time, some eggs may develop fungal diseases. On the first day, they will turn white and then begin to resemble tiny, fuzzy cotton balls. The spread of these fungi can be avoided by using methylene blue on the water.

Hatchability

The changing temperature of the water influences the hatchability of fertilised eggs. The optimum water temperature is between 18 and 27 degrees Celsius. Direct sunlight on fertilised eggs should also be avoided.

During hatching, most of the yellow eggs will gradually turn black and the small fish bodies inside the eggs, resembling coils, will start to be visible. Some eggs will turn greyish white; these are the dead eggs.

Eggs will hatch between five and six days at 18-21 degrees Celsius and in two days at 30 degrees Celsius. The larval fish brush out of their eggs, tail first. Immediately after hatching from the eggs, the yolksat occupies the bulk of the abdominal region of the fish. At this stage, the fish will hang all over the plants, and on the sides of the aquarium.

Once the yolksat has been absorbed, the fish begin to swim free and start searching for food. The fry (young) goldfish are similar in size to newly-hatched mosquito larvae. So, they are suitable food for adult fish too. Spawning goldfish parents also prefer to eat the newly-laid eggs and hatch fry.

Raising the fry

This is the most difficult time in the life of young goldfish. Most of them die at this stage due to the shortage of food. If you are thinking of raising the fry, you must provide them with an abundance of fine powdered food. These food are available in pet shops.

The larval goldfish remain almost colourless for a while, and acquire their colours around the time they are two months old. They then begin to take on a pale yellow sheen. From that time on, their colour changes continuously until they reach adulthood.

Janani Amarasekara

Biting the hand that steals you

Visitors to the pet shop where Micky the moody macaw held court had long been warned that the bad-tempered bird might bite. So it was a shame that a burglar didn't heed the sign.

A man suspected of stealing Micky was traced after the parrot bit him, leaving a pool of blood at the scene.

Micky, an ageing Argentinian macaw known for his vicious temper, was taken from the Frome Pet and Aquatic Centre in Somerset during a break in and has not been seen since.

However, police found enough blood on the floor beside his cage to get a DNA sample.

A 23-year-old man was charged with burglary and animal cruelty offences and appeared before Frome Magistrates. Angus Hart, 45, who has owned Micky for ten years, said it appeared that the cantankerous (irritable) parrot had bitten whoever stole him.

"He's a miserable old man, to be honest with you," said Hart, who has run the pet shop with his wife Jayne, 47, for more than 20 years.

"He doesn't talk much but he can be quite cute and cuddly when he wants to be. However, if he didn't like you he would have a got at you. We've had to put a sign up, warning people he might bite. He did a good job with whoever took him and left plenty of blood at the scene for the police."

Hart was given Micky, who is thought to be more than 50 years old, by a friend in the pet shop business when he retired.

The blue and gold bird has since become something of a visitor attraction, with families flocking to the shop to see the town's most temperamental (moody) bird.

"We're missing him and so is everybody else. We don't know where he is, but he'll be hard work to look after," said Hart.

"It took us eight years to handle him and for him to become relatively friendly to us."

Khaleej Times