how to care for goldfish

Ever wondered how to care for goldfish? It's actually quite simple and once you learn the basics you’ll be ready to raise a happy and healthy pet. When you think of a goldfish you picture a small orange fish that lives in a glass bowl, right? Well, this common visualisation of a goldfish’s home is outdated and is actually very cruel. Not to mention there’s many different shapes and colour variations of these popular fish.

Goldfish thrive in an indoor tank environment where they have enough space to swim and good quality water. Read on below to find out what else your pet fish will need.

Choosing a Tank size for your Goldfish

As previously mentioned, a small bowl is not the ideal environment for a goldfish. Instead they will need an aquarium tank that will accommodate their growing bodies. This tank can be either made from acrylic or glass.

Healthy goldfish can live up to 20 years. Yes you read that correctly – 20 years! Because of this it is important to get the largest fish tank that you have space for and that you can afford. This is especially true if you wish to own a small school of goldfish.

A good equation to work by when choosing a tank is the following:

Gold Fish Tank Sizing Chart - How to care for goldfish

This means that depending on how many goldfish and what length they are,the size of your tank may differ. Also bear in mind that as your goldfish grow you will have to upgrade their tank to give them enough space.

The common goldfish can grow up to 30cm long. That means that one 30cm goldfish would need a 132 litre fish tank just for themselves! The beauty of the formula above is that you can continue to use it as your fish get bigger to make sure there is always enough space.

Goldfish Tank Essentials

One of the awesome things about having a pet goldfish is that you can decorate their tank! There are many different types of landscaping objects for your aquarium to make it a feature of your home.

There are also several practical supplies needed to give your goldfish a comfortable living environment.

What you need:

  • Gravel or pebble substrate
  • Goldfish like to pick up gravel with their mouths and spit it out. It is ideal to choose a substrate that is larger than their mouths to prevent it from getting stuck in their mouths or ingesting it. Alternatively you could choose sand, which is too fine to get stuck.

  • Filter
  • Since goldfish produce a lot of waste it’s integral to use a filter in your aquarium. It will help to remove physical waste particles and will help host beneficial bacteria that remove toxic ammonia from the water.

  • Lighting
  • If there are real plants in your aquarium or if the tank is positioned in a dull area it’s a good idea to have aquarium lighting. It will also make sure you can see your goldfish in all their glory. Your tank should never be placed in direct sunlight as it can raise the temperature of the water.

  • Live or artificial plants
  • Plants in the fish tank will be pleasing to your eye and will provide a comfortable environment for your goldfish. Live plants help oxygenate the water and your goldfish will enjoy nibbling on certain types of plants. Artificial plants are easy to maintain and cannot be destroyed by your hungry goldfish.

  • Aquarium safe decorations
  • Most decorations don’t serve a purpose to goldfish, they just look good. If you want to add a bit of flair to your tank make sure the ornaments are designed specifically for aquarium use. There should be no sharp edges and your fish must be able to swim around them safely.

  • Goldfish food
  • Different types of goldfish food include fresh frozen food, goldfish flakes and goldfish pellets. Some have added benefits such as improving the colour of your fish’s scales.

  • A net
  • You’ll need a net for occasions when you need to scoop out leftover food, waste, and general dirt from your fish tank.

  • Test kit for PH, ammonia, nitrite and nitrate
  • When physical waste builds up in the tank the water will look dirty however ammonia, nitrite and nitrate are invisible to the eye. You will need to test weekly to identify if the levels are safe for your fish.

  • Water conditioner
  • Every time you add more water to your tank it must be treated to be safe. Tap water contains chlorine and other chemicals that can irritate fish but using a water conditioner helps to make it the ideal habitat for your pet.

  • Thermometer and Heater
  • A thermometer and heater will allow you to keep the temperature of your goldfish tank consistent keeping your fish happy and healthy.

  • Air stone
    • Internal Filter – This type of filter is suitable for small aquariums. It sits neatly inside the fish tank using suction cups that stick it to the glass.
    • Hang on back filter – A hang on back (HOB) filter takes up less room inside the tank because it hangs on the outer area of the fish tank.
    • Canister filter – This type of filter is ideal for medium to large tanks as it can filter a large volume of water effectively.
  • In a fish tank with an adequate filter it isn’t necessary to use an air stone because the water will be oxygenated enough. There is no harm in using one if you like the pretty bubble effect it gives. It may also be beneficial if you have a tank that is tall and skinny with little surface area as this shape tank provides your fish with less oxygen than a rectangular or square tank with a large surface area.

Water Quality

Which air would you rather breathe in – smog thick with car fumes and dust or a crisp breeze flowing through a lush green valley? You’d choose the last option, right? Well, funnily enough your goldfish would prefer a clean environment to live in too! As well as visible signs of pollution you must also keep an eye on water PH and ammoniausing a test kit. Keeping the levels of toxic chemicals low is important for sustaining happy and healthy fish.

Cycling Your Fish Tank

If you are a first time fish owner it is important that you cycle your fish tank before bringing any fish home. You can learn how to by looking at this infographic – How to Cycle Your Fish Tank. A step by step guide is also available on the Fish Channel website. Once the tank is cycled you can keep an eye on the quality of the water at home using a test kit. This should be tested on a weekly basis before you do your water change.

Water Filter

As well as weekly water changes, your tank should be fitted with a filter. There are several types of filters however the most common filters for pet goldfish tanks include:

The correct filter is a necessary part of a healthy fish tank. Always make sure that the filter you choose is powerful enough to cope with the size of your tank. Each product will have its specifications listed on the box that tells you what size tank it is appropriate for.

Water Temperature

Unlike tropical fish, goldfish do not need warm water temperatures to thrive. According to The Goldfish Tank (an online resource for goldfish owners) the ideal temperature for water should be around 23°C. The best way to ensure the temperature stays steady despite exterior temperature changes is to use a tank heater.

If you wish to breed your goldfish then you will need to mimic the temperature changes that occur through the seasons. In winter you should keep the temp between 10°C - 12°C and in summer it should be raised to between 20°C - 23°C.

Adding Goldfish to Your Tank

Bringing home new fish is really exciting but for your fish it can be a terrifying experience. They are plucked from their home, placed into a bag and often have to take a bumpy car ride back to your place. The best thing you can do is treat them very gently and let them settle into their new aquarium slowly. The video below shows you the correct way to introduce fish to their new environment.

How To Put New Fish Into A Fish Tank

Goldfish Feeding

It’s essential to only choose quality flakes and pellets that are defined as goldfish food. This is because food for goldfish contains less protein and more carbohydrates compared with food for other fish. Frozen options include blood worms and brine shrimp.

It’s very easy to over-feed goldfish. They are quite greedy and if you let them they will gobble up more food than they need. Too much food can lead to constipation and swim bladder problems.

A small meal twice or three times a day is all they need to be satisfied. Slowly add small pinches of food to the tank for one minute. Avoid adding more food than your goldfish can eat during this time.

Signs that you are feeding your goldfish include:

  • Excess fish waste
  • Uneaten food
  • Unhealthy fish
  • Dirty water
Importance of Water Changes

Tank Cleaning and Everyday Maintenance

Changing the water regularly in your goldfish tank is extremely important. It helps to lower ammonia and nitrate levels, which are toxic to your fish. It also removes physical waste from the water and oxygenates.

How to change the water in your goldfish tank:

What you’ll need

  • Gravel vacuum / gravel siphon
  • 5L bucket
  • Water conditioner


  1. Grab your bucket and place it near the fish tank.
  2. Place the hose end in the empty bucket.
  3. Put the gravel vacuum into the water and start the flow of water according to the siphon’s instructions.
  4. Push the end of the vacuum into the gravel and lift up again quickly. You should see cloudy water being sucked out of the gravel, up through the pipe and into the bucket.
  5. Repeat this process by vacuuming the whole layer of gravel on the base of your fish tank.
  6. Once the water level has gone down by about 20-30% you can stop.
  7. Clean out the bucket and then fill it with tap water that’s close in temperature to your fish tank.
  8. Mix in the water conditioner according to the instructions.
  9. Refill your fish tank using the treated water.


  • Before starting up the flow of water make sure the end of the hose is in the bucket. You may need a second person to help hold it there.
  • Always keep an eye on the bucket to prevent over flowing. You can stop the flow of water at any time by lifting the gravel vac out of the water.
  • Most fish should get safely out of the way however keep your eye out for smaller or slower fish.
  • Avoid pressing the vac into the gravel for long periods of time as pieces of gravel will also get sucked up into the pipe.

Equipment Maintenance

During your water change routine you should also remove your filter, filter sponge, decorations and any other equipment in the tank and rinse them in aquarium water. Please note they should ONLY ever be rinsed in water from the fish tank and not tap water. Tap water is chlorinated and could kill beneficial bacteria that live on your filter and decorations.

Goldfish Diseases

Consistently monitoring the water conditions using your testing kits should ensure that your goldfish is healthy. Just like us, from time to time, fish can become ill. This may be something that has spread from new fish that have been put in the tank or just a general illness.

The Goldfish Tank website provides a valuable resource for identifying and treating goldfish illnesses. Some common illnesses that goldfish suffer from include:

  • White Spot (Ich)
  • Swim Bladder Disease
  • Fin Rot
  • Cotton Mouth
  • Lice & Worms

An aquarium is a beautiful addition to any home and watching fish is relaxing. Taking care of goldfish is rewarding and they make the ideal first pet or for people in apartments.

As you can see there’s more to goldfish care than you may have thought however once the tank is set up, it’s fairly easy to maintain. As long as you regularly check the water conditions and keep a close eye on your goldfish, they should live long and happy lives.

Posted by My Pet Warehouse