How long do goldfish live and how big are they?

Caring for a pet can teach your child about compassion, responsibility, and coping with loss. For their first animal companion, however, it makes sense to choose something small and relatively low maintenance.

A family favorite that fits the bill perfectly is goldfish. Before heading to the pet store, read on for the basics on the Carassius auratus—from life expectancy to dietary advice.

How long can goldfish live?

Shoal of goldfish in a pond. Pet store fish are sometimes kept in overcrowded aquariums and a stressed fish is more at risk of succumbing to disease.
George Melin/Getty Images

Adam Jones, editor of The Goldfish Tank website, suggests that this mainstay of indoor aquariums can have a surprisingly long life, if cared for properly.

“Typically, goldfish have a lifespan of about 10 to 15 years,” he said. Newsweek. “Some varieties can even live up to 30 years.

“Unfortunately, most goldfish don’t live that long due to improper care and inadequate housing conditions. Proper housing facilities are necessary to meet behavioral and physiological needs.”

Jones recommends caution when buying your pet goldfish, as poor housing conditions early in life can shorten its lifespan.

“You want to make sure the breeder doesn’t keep them in an overcrowded or undersized tank.

“Healthy fish should have clear, shiny coloration on their bodies and they will swim around the tank without any excessive effort.

“An aquarium that is too small can stunt the growth of your goldfish, cause them to come to the surface and can even lead to premature death.”

How big are goldfish?

Aquarium native hardy goldfish, Red Fantail
A Fantail goldfish. Goldfish can grow to 10 inches or more in ponds, but are unlikely to grow to that length if kept in an aquarium.
EuToch/Getty Images

The size of a goldfish depends on “care and treatment of the fish,” as well as “breed and genetics,” according to Jones.

He added: “Goldfish kept as pets contained in smaller indoor tanks usually grow to about 1-2 inches in length and never really exceed 6 inches. However, in ponds they can grow to well over 10 inches. inches.

“For optimal growth, your goldfish needs approximately 29% protein and 12% fat in its diet. If you follow this, your goldfish should grow to 2 inches over a six month period and 3 inches at the end of his freshman year.”

The largest goldfish on record was owned by a man in the Netherlands and measured 18.7 inches long in 2003.

Goldfish that are over 1 foot long are not that unusual. In July 2021, Minnesota officials urged pet owners to stop throwing unwanted goldfish into lakes or ponds.

They highlighted the problem by sharing footage of goldfish that grew to enormous size after being released, damaging water quality and plant life in lakes.

What do goldfish eat?

goldfish swimming in a pond
Goldfish swimming in a tank. It is easier to prevent your fish from overeating if it is not in a pond.
Mirek Kijewski/Getty Images

Goldfish eat a variety of insects, plants and crustaceans. For pets, Jones recommends a mix of flakes, pellets, live foods and vegetables.

They are also “opportunistic feeders”, he said, and will continue to eat “even if it is to their detriment”.

He added: “By keeping a goldfish in an aquarium rather than a pond, you will be able to monitor their diet and make sure they don’t overeat because you will be controlling their diet.

“Although you should always feed goldfish that live in ponds, they are open to the environment around them. This means that they feed on insects that fall into the pond water, as well as seaweed.”

How to Care for a Goldfish

Goldfish in an aquarium with green plants, snag
Goldfish in the aquarium. Keep a close eye on your pets for any changes in appearance or behavior. This will help owners address concerns before they become major health issues.
sergio_kumer/Getty Images

Before buying a goldfish, consider the size of the tank – not the bowl – that you will need to place somewhere in your home.

“Each fish should have a minimum of 6 gallons of water for themselves, and the tank should ideally be no less than 10 gallons. So the more fish you have, the bigger the tank will need to be,” Jones said. .

Your tank will also need:

  • A thermometer to make sure the water stays at the right temperature
  • An aquarium filter to prevent the water from becoming toxic
  • Sufficient hiding places to maintain your fish’s natural instincts

The tank should be cleaned regularly. “It just requires you to change about 10 to 15 percent of the water and refill with dechlorinated water,” says Jones, who offers more tips for new goldfish parents online.

goldfish alone goldfish in the aquarium
Your goldfish tank should hold at least 10 gallons of water. Each fish you add should have its “own” 6 gallons or more.
Altinosmanaj/Getty Images


Not all news on the site expresses the point of view of the site, but we transmit this news automatically and translate it through programmatic technology on the site and not from a human editor.
Back to top button