Complete Goldfish Care Guide for Beginners


When starting out with fish keeping, many of us have bought our first Goldfish, only to see it die in about a week. It has often been difficult to even determine what went wrong. However, it is not very difficult to keep Goldfish healthy, even if you are just starting out.

Many Goldfish breeds can live for over 10 years with the right care. You will need to know how to:

  • Set up a proper aquarium
  • Cycle the tank and ensure proper water requirements are met
  • Choose healthy Goldfish
  • Keep the Goldfish aquarium clean
  • Take proper care in daily routines

Once you know what your Goldfish need to be comfortable and healthy, it takes a lot of stress away and you will gain confidence to keep them in a good condition. This page will give you all the info you need, especially if you are a beginner.

Step 1: Setting up an appropriate tank for the Goldfish

Contrary to what people think (and what many fish stores will have you believe), Goldfish, like any other fish, are supposed to be kept in an aquarium with large enough space for them to move around and turn freely, without any restrictions to their movement. Fish bowls are simply not an option, unless you transfer the Goldfish to a larger tank within a week or two of getting them.

Ideally, you would set up an aquarium before you even buy your fish. Because bowls are basically death traps for fish, by the time you arrange for a larger tank, you will need to follow some precautions with your bowl. I’ve written a detailed article specifically on this topic, which you can read by clicking here.

When your aquarium arrives, you will need to put in some simple but important equipment. First off, you will need an air pump, along with an air stone. This will help in circulating fresh air into the tank, enabling the fish to breathe freely. Next, you will need a filter for your tank. You can choose from a range of different types and sizes of filters depending on the size of your aquarium. Many filters also provide a continuous flow of fresh air to the tank.

Watch out though, if you don’t have an air stone or a filter that’s supplying air, the Goldfish will start to suffocate in as little as a few minutes! You can notice when this happens, because the fish will start breathing heavily and their mouths will open and close much faster than they usually do. When the oxygen supply really runs out, they will even come to the surface and try to gulp in air directly from above the water! You need to keep an eye out for this, as when this stage arrives, they cannot survive for very long!

However, if you are this situation does arise, and for some reason you can’t immediately start an air pump/filter, you can remove 20%-30% of the tank water and replace it with fresh water. The newer water will have more dissolved oxygen, and should help the fish regain their breath in a couple of minutes.

Goldfish will do well when they have some areas of the tank completely to themselves. That is, places from where they can’t see you, nor can you see them. This can be accomplished by setting up decorations around the tank, especially at the rear corners. When the Goldfish feels scared or stressed, it can go there and feel safe.

A light source is essential, as it will enable the Goldfish to see their surroundings, both within and outside their tank. They should be able to see outside the tank too, because if something or someone suddenly moves or a loud noise is suddenly heard, they will get startled and dart around the tank without looking at what’s in front of them. As a result, they can crash into the glass, decorations, stones, filter and what not. This can cause serious injuries to them.

 You will also need an aquarium heater and small stones to line the bottom of the tank with. All this equipment will go a long way in helping your Goldfish thrive! To find out what kind of aquarium equipment is best for your requirements, click here for my complete guide to freshwater aquarium equipment for fish.

Step 2: Cycling your Goldfish tank

The next step to care for your Goldfish is to cycle your tank. When there is decaying matter in the tank, such as uneaten fish food and fish poop, ammonia starts building up. This then turns into nitrites and nitrates. And when any of these gets produced in high concentrations, they can prove deadly to your fish. Most fish owners don’t realise how the nitrogen cycle works, as a result of which the fish end up dying way before their average lifespan. Not being aware of the nitrogen cycle has got to be the number 1 killer of aquarium fish worldwide.

Help, however, is at hand. It may seem like a complicated topic at first, but I have written an in-depth article on how the nitrogen cycle works and how to check whether the ammonia, nitrites or nitrates are high. If any of these are too high, I’ve also listed ways to bring them back down to tolerable levels for your Goldfish. You can click here to read about the nitrogen cycle.

Step 3: Ensuring the water is fit for your Goldfish

The next step to care for your Goldfish is also ideally done before the fish arrive. Your Goldfish will thrive when provided with certain water parameters. Some of them have been discussed above, although there are some more factors that need to be addressed.

There are certain things which need to be measured regularly. These parameters need to be kept within a certain range, or will prove to be dangerous for the Goldfish. They are: Temperature, Water Hardness (GH and KH), as well as pH. This link will take you to an article where you can learn how to increase or decrease any of these parameters, as the situation arises.

The tolerable range for these factors is different for each specie of fish. However, it is similar for all Goldfish varieties. You can click here to read the Goldfish Breed care guidelines, where I’ve mentioned the ranges that Goldfish thrive in, along with other factors.

Step 4: Choosing a healthy Goldfish

Taking all these precautions will be pointless if the Goldfish you buy isn’t healthy to begin with. Getting a sick fish home is almost certainly going to kill it, especially if you are new to fish keeping. What’s worse is that a sick fish can also pass on the sickness to your other, healthy fish.

You can determine whether a Goldfish is healthy by looking at its fins. All the fins and the tail should be opened up and away from the body, not clenched towards the body. The Goldfish should also be swimming about freely. Swimming in all directions, breathing comfortably (not going to the water surface, unless to feed), looking around at the stones on the tank floor and moving pebbles about with their mouths are all good signs.

What a Goldfish should not be doing, however, is it should not sit at the bottom of the tank or on a decoration/plant, it shouldn’t be gulping for air at the water surface, breathing shouldn’t be stressful (mouth opening and closing rapidly and in quick succession), fins/tail shouldn’t be closed and clenched towards the body. Don’t get a Goldfish showing any of these symptoms, as it could be sick.

In fact, you would be better off not getting even a healthy looking fish from a tank that has sick fish at the store. This is because if the sick fish has infected the healthy fish, its health could go south very fast. And that’s something you don’t want to deal with when getting a new fish. For slightly more experienced fish keepers, I’d recommend setting up a quarantine tank, just in case your new fish is sick. Once set up, it will come in handy when your older fish fall ill too. Here is an article on setting up and running a quarantine tank.

I recommend keeping Goldfish that are closer to their natural ancestors, such as Comet Goldfish and Shubunkins. You can view their profiles here. The reason is simple. The more varieties and mutations of Goldfish we breed that are different in body shape, size and features to their natural ancestors, the more susceptible to they are to diseases.  

Step 5: Transferring your Goldfish to the tank properly

As we have seen in step 3, Goldfish (or any fish, for that matter) have some parameters that need to be kept within specific ranges. So when you get the fish from the store, there is a proper way of transferring it to your tank.

To begin with, ensure that the water in the destination tank is fit for the Goldfish. (Be sure that any other species in the destination tank are compatible with Goldfish, and have similar water parameter requirements! You can check which species are compatible with your breed of Goldfish as tank mates over here.)

The water in the store’s tank and your tank will be different. They will both have different temperatures, water composition, hardness, etc. The store will give you the fish in a plastic bag. You need to empty the bag, both the water and the fish, into a bucket. Then, you can take half a mug of water from your tank and put it in the bucket. Wait 5 minutes, and add another half mug from your tank. Wait 5 more minutes and repeat. You need to keep repeating this until more than half the water in the bucket is from your tank.

The reason you should do this is to acclimatize the new Goldfish to water from your tank. Now, when most of the water in the bucket is from your tank, the new fish is in a similar environment to your tank. So you can take the fish out in a net and transfer it safely to its new home, the destination tank. After transferring all the new fish to your tank, you can throw away the water left in the bucket. (Or use it to water plants or something)

Step 6: Feeding your Goldfish appropriate food and quantity

Goldfish eat both flakes (that float on the surface) and pellets (that sink to the bottom of the tank). If you are getting pellets, their size should be small enough that the Goldfish can swallow them whole. Just be sure to get the food that is specifically made for Goldfish and/or Koi (As Koi have similar nutritional requirements to Goldfish). Goldfish do not have stomachs, so they tend to overeat. You can feed them in limited quantities 2 to 3 times a day. The quantity of food should be such that the Goldfish can eat all of it in about 1 minute.

Watch out if there are one or two aggressive feeders in your tank, meaning they eat everything up quickly and barely leave anything for the others. You can spread the entire quantity of food all over the water surface to avoid this. You can turn off the filter while feeding, for not more than 5 minutes, otherwise the uneaten food particles can get sucked into the filter or get stuck deep in between the gravel because of the water current generated by the filter. There, they will rot and rapidly foul the water.

While it is recommended to feed the commercially available food as a staple diet, you can feed the goldfish tiny pieces of meat too. The meat can be from fish, shrimp or even chicken. You have to cut up the pieces such that they are easily swallowed whole by the Goldfish, as they do not have teeth to chew them up. If they can’t swallow them directly, they will just ‘chew’ on them for a while and then spit them out. And nothing depletes water quality as surprisingly fast as meat left to rot in the water.

They will also eat tubifex worms and bloodworms, both freeze-dried and alive. Goldfish don’t require lots of protein, so it is best to feed them meat/worms not more than 3 times a week. You will be feeding them 2 to 3 times a day, which is 14 to 21 times a week, right? So give meat only 1 to 3 times in a week. And each of those feedings should be on separate days, to avoid protein overdose.

It is a good practice to feed Goldfish peas every week. They have high fibre content, which makes the fish poop easily and avoid constipation. I can tell you from personal experience that constipation in fish is neither easy nor quick to cure. It often leads to the death of the fish. So, prevention is always better than cure.

You can boil the peas until they are super soft (remember, Goldfish do not have teeth). Then remove the outer shell of the peas and chop them up into really tiny pieces. Feeding them peas at least once a week will go a long way in preventing nasty situations in the future.

Step 7: Keeping your Goldfish comfortable and stress-free

You want to keep your Goldfish happy and stress-free at all times, because when a fish is stressed, its immune system becomes weak, swinging the door wide open to a range of diseases and infections. There are many factors that can cause a Goldfish to come under stress. We have seen some of these factors such as poor water quality, improper nutrition, lack of hiding spaces, etc.

I have prepared an in-depth list of factors that can cause your fish stress, as well as how to overcome them. Along with these, I’ve also explained what signs a fish exhibits when it is under stress over here.

Step 8: Keeping the Goldfish tank clean

One of the reasons I believe fish are the best pets is that they do not require daily cleaning. Even the busiest of us can find the time to do the regular maintenance. You just need to replace some of the water in your tank with fresh, clean water. How much water needs to be replaced depends on what species of fish you have. Goldfish are very messy. They eat a lot, poop a lot and are slow swimmers (The fancy varieties).

So if you’re not careful with how much food you’re putting in the tank at once, the excess food pellets will sink to the bottom of the tank before the Goldfish can get to them and get lodged in between the stones, dirtying the water. So for Goldfish, I’d recommend at least 30% water changes every week.

This percentage is, of course, assuming that your tank is not overstocked. If you have a bit more fish than the recommended amount, you will need to do more water changes. More info on overstocking in step 12.

Step 9: Taking proactive measures to avoid any accidents and health issues for your Goldfish

Goldfish are very susceptible to chemical poisoning. Care should be taken not to let any chemicals, other than those specifically made for aquarium use, to enter the water. Common ways dangerous chemicals can enter the water are soap or detergent residue after cleaning the tank/equipment. Only warm water must be used to clean the tank and other equipment like buckets, nets and filters. Chemicals must be avoided as much as possible. If you still do need to use them, be sure to rinse the equipment with clean water multiple times in order to remove any residue.

Air fresheners must be placed away from the fish tanks. The tanks shouldn’t be placed in kitchens, as there are a lot of fumes that are emitted while cooking. Insecticides like fly and bug sprays should be used away from the fish tanks and the tanks should be kept covered while using them.

When using tap water to perform water changes or add water to a new tank, be sure to use a dechlorinator to remove chlorine from the water. If you don’t have access to a dechlorinator, keep the water still in a bucket for 24 hours. The chlorine will escape from the water into the air.

Step 10: Looking out for Goldfish health problems

We love to spend lots of time admiring our finned friends. While doing so, it pays to observe how they are feeling too. For example, if you notice your goldfish gasping at the surface for air, being lethargic, having a bloated tummy, having sticky faeces, swimming tilted to one side or upside down, or having small white spots on its body, it could be a cause for concern. These are all signs that your goldfish could be ill, and immediate corrective action needs to be taken.

Step 11: Treating when you see signs of any health issues on your Goldfish

Depending on what is wrong with your goldfish, you may need to increase the water temperature, add medication or salts into the water, reduce feeding or even set up a hospital tank.

While all this may make it sound difficult to diagnose and treat your goldfish, don’t worry! I’ve written an article on Common health issues with Goldfish and how to treat them. You can read it here.

Step 12: Switching to a bigger Goldfish tank when the time comes

There is a limit to how many Goldfish you should put in a tank. Depending on the variety, Goldfish can get to be between 4 inches to 12 inches long. And no, an 8 inch long Goldfish is not twice the size of a 4 inch long Goldfish. It is twice as long, but its body mass can be up to 4 times that of a fish half its length.

This means that the 8 inch one will eat up to 4 times as much food and poop up to 4 times as much as the 4 inch one. So, if you have a single 8 inch Goldfish in a tank and four 4 inch goldfish in another tank of the same size, you will need to change the same amount of water to keep both the tanks clean. And yes, the tank with the 8 inch fish will probably look empty and you will want to add more fish. This is why it is important to do a bit of research on the varieties you are getting. I have a Goldfish Breed Guide where you can read about and compare the different breeds of Goldfish.

For a single 4-inch Goldfish, I would recommend having at least a 15 Gallon long tank. (But don’t keep just one though, the little fishy will need some friends) So for each additional 4-inch Goldfish you need to increase the tank size by 10 Gallons. For example, to keep four 4 inch long Goldfish happy, you will require a 45 Gallon long tank. (15 Gallons for the first fish + 10 Gallons each for the other 3 fish, i.e. 30 Gallons = 45 Gallons)

Now, considering the previous example and how much poop an 8 inch Goldfish can produce, a single 8 inch long Goldfish will need a 45 Gallon tank to have enough room to move about freely, and also have enough water in the tank not to have massive fluctuations in water quality.

Now you can go ahead, armed with new information and knowing that you will be giving your Goldfish the better life that it deserves, along with the peace of mind that you deserve. Good luck!

Syed Baseeruddin Hyder

I’ve been keeping fish and invertebrates in aquariums for over 5 years. Over the years, I’ve kept more than 15 different species of fish and invertebrates. Through ParadiseInATank.com, I hope to guide new and experienced fish keepers alike with as detailed information as I can get.

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