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How to look after Goldfish | Kellyville Pets



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This comprehensive care guide will show you how to look after a Goldfish in 3 easy steps


Fast Facts:

How long will my Goldfish live? 20 years

How big will it grow? 20cm

What size tank is recommended for my Goldfish? 80L capacity

What does a Goldfish eat? Specially formulated goldfish flakes or pellets

Goldfish Housing

Goldfish are a freshwater species that thrive in a cold water environment. To avoid temperature changes, particularly in smaller tanks, it is important that the aquarium be kept out of direct sunlight. 

Goldfish can initally be kept in a small 20L tank while they are juveniles. However, they will quickly grow and within a year will need to be upgraded to an 80L tank or larger. For a 20L tank, you can initially keep 1-2 small goldfish. Once upgraded to an 80L tank, or if you choose to start with a larger tank, 6-8 goldfish can be kept, even at full size.

Goldfish will grow to approximately 20cm in length. It is a good idea to provide both natural and artificial plants, however Goldfish will eat some natural plants. Ornaments, rocks or logs should also be provided to allow them a hiding space.

Goldfish Care

Goldfish are a true coldwater fish and prefer temperatures between 10°C–20°C, in reasonably hard, alkaline water. 

A pH of 7.0 – 7.5 is the desired range for Goldfish. Aquarium Salt can also be added to your Goldfish aquarium periodically. This will assist in keeping satisfactory water hardness and a stable, alkaline pH. 

They require large, well filtrated aquariums, with approximately 80 litres for the adult size goldfish varities. Goldfish are heavy feeders, making them high waste producers. This means they require efficient filtration of a suitable size to maintain water quality and oxygenation. By utilising a good filtration system, you can ensure that all water is constantly filtered both mechanically and biologically through the use of the nitrifying bacteria in the filter media.

An aeration system can be used (such as air stones) to boost oxygenation in the water if the filter is not creating enough movement or bubbles around the surface. This is important due to the high amount of waste goldfish produce. 

It is suggested to maintain ammonia and nitrite levels of 0. To achieve this, it is recommended that weekly testing is done. To ensure that the tank stays clean and proper environmental balance is maintained, a 30% water change should be undertaken every two weeks.

Goldfish Food

Goldfish are omnivorous. In the wild, the natural diet of the Goldfish is a combination of vegetation and live food small enough to fit into their ever hungry mouths. 

In captivity, Goldfish will appreciate a wide variety of foods and generally eat anything offered to them. They have a rather simple digestive system and some foods may contain more nutrients than a Goldfish is capable of digesting and using effectively. 

Providing your Goldfish with a balanced diet of flake, pellets, veggie matter, live and frozen foods, will ensure the best condition and health for them. A good diet plays an important role in the health and well-being of Goldfish, with small, regular feeds the best method.

Did You Know?

The Goldfish is a fish that belongs to the family Cyprinidae. Goldfish have been kept in captivity for hundreds of years, longer than any other fish in fact. Since they have been kept in captivity, many new breeds and colours have been developed. Currently over 120 varieties of Goldfish exist. 

Note: When selecting a filter, ensure the current is adjustable. The current should not be too strong if fancy or unusual goldfish types are to be kept as fast currents can make swimming difficult for some of these fish.


We have created a Shopping list to show what you need to look after Goldfish:

  • 80L tank
  • Filter
  • Gravel
  • Plants
  • Rock
  • Driftwood
  • Water conditioner
  • Bio culture
  • Net
  • Gravel Cleaner
  • Magnet Cleaner
  • pH test kit
  • Amonia test kit
  • Nitrite test kit
  • Nitrate test kit
  • Dry goldfish flakes
  • Frozen spinach
  • Goldfish pellets

Common health issues in Goldfish

Fin & Tail Rot: Usually due to poor water conditions, however can be caused by other problems. As the fin rot can progress and attack the body, it should be immediately addressed with an antibacterial treatment.

Cloudy Eyes: The eye becomes cloudy to the point of turning white, and the fish will lose its vision. Generally caused by parasites or stress, so water quality should be tested and remedied as needed.

Red flags

Is your Goldfish showing any of the signs of disease or illness? If yes, please contact your vet.

  • Sitting on the bottom of the tank (check temperature)
  • Clamped fins (check water quality)
  • Poor appetite (check temperature)

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At Kellyville Pets, we encourage responsible pet ownership.

CARE GUIDE © Copyright 2016 Kellyville Pets - All information found in this care guide is based upon our own experience. The information provided is not the only information available. In any medical situations,  you should always consult your vet, including questions regarding your pet's diet.