Fishbowl Adviser

Goldfish Care Guide (for Beginners)

Scientific NameAverage Lifespan Average Adult SizeWater Temperature pH
Carassius auratus5-15 Years1-4 Inches68°-74° F7.5

If you’re about to buy your first goldfish, then you need to get informed and prepared to welcome your new pet into your home. However, even though it may seem that taking care of one little goldfish is easy – it isn’t that easy. To help you prepare, take a look at the goldfish care guide that we made especially for beginners.

Goldfish swimming

Choose Healthy Goldfish

The main part of caring for your new goldfish is to get a healthy one. You can’t pick a fish that you fall in love with at first sight. Instead, it’s best to carefully look at the fish you want to get. Getting a sick fish will require solid nursing skills that you probably don’t have. Of course, as a beginner, you can’t recognize the best fish among all, but you can look for certain signs that can indicate what kind of fish you can get. To get a healthy fish, you will need to look for the following criteria:

  • Constantly on the move and looking for something to munch on
  • Swims around actively
  • No floating problems
  • No sinking problems
  • Perky look
  • No genetic defects (bent back, missing anal fins, or collapsed mouth)
  • Not living in dirty water conditions
  • Not living in the same tank with sick or dead fish
  • No obvious signs of illness (red marks, white spots, bloody looking fins, and similar)

Goldfish Tank Setup

Probably the most important factor of your goldfish care is your fish tank setup. The way you set up your fish tank for the goldfish you get can influence its health, so you will need to get it right from the start.

It’s best to set up your fish tank even before you get your first goldfish. Of course, you’ll be able to adjust some factors and conditions later, but having the proper fish tank setup when you get your goldfish is very important. Let’s take a look at the essential things you need to consider for your tank setup.

Goldfish Tank Size

Can I keep a goldfish in a bowl? – The answer is no. One of the common misconceptions is that goldfish can live in bowls or small tanks. Bowls are not an option for your goldfish. You will need to get a proper fish tank that has enough space for a goldfish (or multiple) to thrive in. While the bowl does provide great viewing, it actually never considered the health or welfare of the goldfish and is one of the worst designs to keep goldfish.

Goldfish are one of the best fish to keep in a bowl, but only if there is enough space. Because of the bowl’s round and tapered sides, there isn’t much surface area for oxygen exchange. They actually grow very fast and can become large, and goldfish need enough space to swim freely as they want, which means your tank will need to be able to provide that. Not getting the proper tank size will slow your goldfish’s growth and development, and even shorten the usual goldfish lifespan, which makes choosing the size the most important part of your setup.

Tank sizes are classified and labeled according to the amount of water they can hold. The size of the fish tank can vary based on the goldfish breed, but the minimum tank size for goldfish is 20 gallons for hardy or common goldfish and 30 gallons for fancy goldfish, with the rule of adding an extra 10 gallons for each new goldfish you get. Keep in mind that goldfish are community fish, which means they will thrive if they have company, so getting a bigger tank of 30 or 40 gallons from the start might be the best thing to do. One last thing you’ll need to consider is if you plan on getting your goldfish pregnant, in which case a bigger tank is a must (plus an additional tank for the spawning should also be on your list)

Goldfish Tank Temperature

The temperature of your goldfish tank is very important. They are not cold water fish, but they are eurythermal and can thrive and grow in a wide range of temperatures. Some breeds like fancy goldfish are used to tropical water temperatures, so you can keep them with any tropical fish you have. However, at high temperatures, their metabolism gets higher, which means goldfish need more oxygen (warm water can carry less oxygen) and they will produce more waste.

Water and Filtration Requirements

Having a filtration system in your tank is highly recommended for any type of fish. Filters create a place where beneficial bacteria can grow and keep the water quality in good shape longer, and beneficial bacteria are actually what helps keep your water safe.

You will still need to change water even if you place a filter, but filters will provide a healthy environment that goldfish like. To perform a water change, you will need a siphon that can be connected to the sink from your tank (of 20 gallons and above). On top of that, you will also need to regularly clean your fishbowl or tank and make sure there is no waste.

If you’re planning on using tap water for your tank, you should be aware that it might contain chemicals, with chlorine and chloramines being the most common ones. If that is the case, you will need to treat it with an appropriate water conditioner.

Apart from a filter, you should also get an aquarium heater that will keep the temperature of the tank steady and prevent any changes that might stress your goldfish.

Additional Tank Equipment

You can also get an aquarium light that will keep your goldfish and plants thriving. Another useful tank addition is bubble walls. They can increase oxygen and even add some sparkle to the back of your tank. However, they do need an air pump and airline tubing to work properly.

For decoration, you might want to consider getting a sand substrate, which is an alternative for regular pea gravel most people get. Pea gravel is something you should avoid when getting a goldfish, as it can be a choking hazard. The sand will give the fish something to forage in and decorate your tank without adding the risk of choking.

You can also add live plants to decorate your tank and, at the same time, create safe hiding places for your goldfish. Regular decorations can actually be dangerous to goldfish because they can leach contaminants in the water or get goldfish stuck in them. Because of that, live plants are a much better option, but you need to make sure that they are goldfish-friendly.

Goldfish and bubble

Adding Goldfish to Your Tank

Regardless of the place or shop where you got your goldfish – all fish must be quarantined and placed in a separate tank if you already have fish in your main tank before you can keep them in your intended tank. Why?

Well, first, the quarantine will give your new fish time to rest before getting to meet new fish. Apart from that, it will keep all of your fish healthy and disease-free – your new fish won’t catch anything your old fish might have, and your old fish won’t catch any disease your new fish might carry with it.

Before you got your new pet, your goldfish was in a tank with other fish that might have carried an illness and transferred it to your pet. The quarantine will help you treat your new fish for common goldfish diseases. In some cases, your supplier might have already fully quarantined and treated it for any disease, but in most situations, you will be on your own (with the help of your veterinarian).

Once you’ve taken care of this, you can put your goldfish in its new tank. Don’t do it right away. If you’re keeping it in a plastic bag, let the bag float in the water for 15-20 minutes so that it can adjust to the temperature. After that, you can open the bag and put your new fish in the tank. If you are going to keep your new fish in a separate tank while in quarantine, make sure it has the same conditions as the main one.

Goldfish Feeding

In terms of feeding, you will only need to feed your goldfish once a day by pinching a small amount of food in the tank. If it seems like your goldfish is still hungry, then you should continue feeding it for 2 minutes or when it loses interest. However, keep in mind that goldfish can eat as long as there is food, so you need to make sure you do not overfeed them.

Goldfish Diseases

There are many goldfish diseases and health risks you need to be aware of when keeping them as pets. Among some of the most common goldfish diseases are:

  • Fungal infections – the most common disease fish can get. Fungal spores naturally live in fish tanks, and their infections show as a white cotton-wool-like growth on the fish’s skin, gills, mouth, or fins, but it only comes as a second disease, so you will need to treat the fish disease or injury to treat this.
  • Cottonmouth – a bacterial infection that affects tropical and cold-water fish by giving them lesions – white or greyish-white spots (later they become yellow and brown) on their heads and mouths. Similar to that, slime disease is a parasitic disease that happens with the overproduction of mucus coating. To treat these conditions, you will need a water change and aquarium salt.
  • Ulcers – an inflammation of the external tissues that will look like sores and caused by bacterial infection, bacterial sepsis, bacterial erosion, parasites, physical injury, or any chemicals that can be in the water (nitrate, ammonia, or bad pH levels).
  • Slime disease – a parasitic disease that causes an overproduction of mucus coating (it appears as grey or white mucus coating), rapid breathing, and in some cases suffocation.
  • Dropsy – a fatal disease for fish that is displayed as a swelling of the fish’s abdomen.

Two Goldfishes

Final Words

Taking care of a goldfish is not an easy task. You need to create a proper environment for the goldfish, and constantly make sure that their tank is clean and without any chemicals in it. And you need to constantly check if they have any disease that might shorten their lifespan. All in all, keeping a goldfish is an important task, so you need to make sure you are prepared for it.


  1. Caring for Your Goldfish – PDSA
  2. How to Take Care of a Goldfish – PetMD


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