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Goldfish care guide

Goldfish care guide

Goldfish can make fascinating pets. They live in cold water and do not require extra heating. They're great for beginner fish keepers and can be remarkably beautiful.

Environment and housing

You need to provide a suitably sized environment for your fishAn aquarium is the most important aspect of goldfish care and it needs to be a suitably sized environment for your fish. We recommend a filtered, cycled tank (check out our article on The Nitrogen Cycle) rather than a bowl. Narrow necked bowls or tanks don’t create enough of a surface or swimming area.

Juvenile goldfish should have a minimum tank size of 75L per fish plus 40L for each additional fish. Fish will need a larger tank as they grow to accommodate their size (an adult goldfish may grow up to 30cm in length).

Maintaining a consistent pH level, temperature and aeration will help to create a healthy environment for your fish. Goldfish are bigger waste producers than other fish of comparative size; so it's imperative to make sure that you have a good filtration system and keep your tank appropriately stocked.

Other environment requirements include gravel or substrate, plants, and sheltered areas which may be ornaments, aquatic-friendly rocks and driftwood. An air pump can be added to assist water aeration, these are attached to an air stone to create surface agitation and create a bubble effect. Tank lighting is optional, but it helps to show off your fish and their setup to its full advantage, and is a necessity for any plants.

Aquarium placement

Place your aquarium in a stable environment, one that doesn't have significant changes in temperature or in the path of drafts. The tank shouldn't be in direct sunlight as this can cause excessive algae growth and will affect the temperature of the water.

Never use fly spray, air fragrance or other aerosols around your tank. These can be fatal to your fish. Fish can also get startled by loud noises and vibrations (like running past or tapping on the aquarium itself) so place your aquarium somewhere it will be relatively undisturbed.

Make sure you set your tank up near a power supply.


Goldfish need more carbohydrates than other fish so it is important that you feed a “goldfish” specific food. A high quality pelleted or flake food is a great staple, but like us, goldfish like variety. Frozen goldfish food such as brine shrimp and bloodworms may also be fed.

Goldfish should be fed at least once a day and never more than they can consume within 3-5 minutes. Check the feeding instructions on the food label as it can vary depending on the type of food.

A great tip is to hold the flake or pellets underwater for a few seconds before releasing as the food will absorb water and sink before the fish start feeding. This prevents the fish surface-gulping which can lead to potential bloat and swim bladder concerns.

Check your filter and replace material as necessary but never all at onceHabitat maintenance

When changing out water, changing 20-25% of the water once a week in a well filtered tank. It is best to use a gravel siphon to do this as it can be used to vacuum your gravel; removing additional waste material.

To keep your tank looking tip top, clean the inside of the aquarium glass (or acrylic), being sure to use the appropriate cleaning pad so you don't scratch the surface. You should also clean your ornaments in dechlorinated water (when doing your water change, keep some old tank water aside and use this for any ornament cleaning) and tidy up your plants – pick off any brown leaves or decaying material.

Once you've completed your general maintenance, it's time to top up your tank with more water to replace what was removed during your water change. We recommend putting the fresh water in a bucket and pre-treating it with the required dose of water conditioner before adding this water to your tank. This helps to ensure that no chlorine, chloramine or heavy metals get added into your tank. Never completely clean out your whole tank, there are millions of beneficial bacteria which maintain the equilibrium of your tank’s health.

Check your filter and replace material as necessary but never all at once. There are biological supplements such as Nutrafin Cycle which should be added to your tank to maintain its health. Biological supplements are used more regularly when setting up and cycling a new tank, but is a great addition to your general maintenance routine.

Regular water testing is important, as it can help you notice if something is going wrong in time to fix it. It's especially important when adding new fish. Test your pH, kH, Ammonia, Nitrite and Nitrate regularly (or as previously mentioned after new fish have been added), and don't forget that all Animates stores offer free water testing services.


These items can be dangerous for your fish:

  • Sharp edged ornaments
  • Aerosols
  • Metals
  • Foreign objects from beaches and rivers
  • Glass tapping
  • Loud and sudden noises or vibrations (construction etc)
  • Always wash your hands (and rinse well) before and after handling your tank contents

The signs of a healthy goldfish are:

  • Upright fins
  • Active and alert with normal movement
  • Feeds well
  • Healthy scales with no lesions or sores

The signs of an unhealthy goldfish are:

  • Gasping at the top of the tank
  • Swimming abnormally
  • Scratching or body flicking
  • Small white spots on the skin or fins
  • Droopy, torn or frayed fins
  • Lesions or cotton wool looking substance on the body
  • Swollen eyes

Recommended supplies

  • Tank setup (with filter)
  • Aquarium only bucket
  • Variety of high quality food
  • Water conditioner
  • Biological supplement
  • Cleaning equipment
  • Multi-plug with surge protector
  • Air pump and airstone (optional)
  • Gravel siphon
  • Gravel
  • Ornaments
  • Thermometer
  • Fish nets
  • Water test kit
  • Animates care guides

Use this checklist to make sure that a goldfish is right for you and your family:

  • I have the appropriate sized tank that is required for these fish.
  • I understand that this goldfish can not be housed with all aquatic species.
  • I can commit to looking after this/these goldfish for up to 20 years.
  • An adult can provide primary care for this pet.

Average size: Goldfish have the potential to grow up 30cm+ in length
Life span: Up to 20 years