How to Setup a New Goldfish Tank?

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Which is the best kind of tank for Goldfish? Tricky question, eh? While Goldfish are some of the most popular aquarium creatures, most people still don’t realize what it takes to rear healthy and vibrant Goldfish.

Yes, setting up a Goldfish tank can be a little confusing. What tank size is appropriate? Will your most preferred substrate affect your pets? Do you really need a filter? These are merely some of the questions you’ll need to answer before setting up your tank.

How to Setup a New Goldfish Tank?
How to Setup a New Goldfish Tank?

In light of this, here’s everything you need to know about establishing an ideal Goldfish tank:

Choose the Right Aquarium Size

As you may know, keeping Goldfish in an inappropriate tank will ultimately affect their health and well-being. The size of your tank should fit the current as well as the potential size of your fish. It’s crucial to appreciate that the goldfish sourced from pet stores are usually young and haven’t reached their full adult sizes.

If anything, fancy goldfish can grow up to 8 inches (in length), while common goldfish can get as big as 10 inches (in length). Other goldfish species can grow even bigger. This is why it’s impractical to keep goldfish in a goldfish bowl.

So, what the right tank size for goldfish? For comet and common goldfish, you should go for a 30-gallon tank measuring at least 4 feet long. Of course, the bigger the size the better.

Mind you, comet and common goldfish tend to become quite large, so if your keeping more than one fish, add an extra 12 gallons for every additional goldfish. With fancy goldfish, the best tank size is 20 gallons in volume and 3 feet long.

Now, considering the above information, the most appropriate aquarium sizes are:

  • 40+ gallons when keeping two comet or common goldfish
  • 30+ gallons when keeping two fancy goldfish

Set Up the Fish Tank

Once you’ve bought the right aquarium for your goldfish, the next step is to set it up. You ought to take a lot of caution at this stage, as it will ultimately determine how successful your project becomes. Here are several pointers to consider:

Choose a Good Location

Walk around your house, taking the time to decide which spot is most ideal. Remember, your fish tank shouldn’t get exposed to direct sunlight or a draft. After all, direct sunlight speeds up algae and bacteria growth by increasing the tank’s water temperature.

On the other hand, drafts can pose a serious danger to your goldfish, especially during the cold months of the year. Take note that you’ll need the tank to be close to a power source for the filter and any other device you’ll need. Other than that, the ideal location should be able to sufficiently accommodate the tank’s size.

Add Substrate

After placing your fish tank in an appropriate location, you’ll need to fill it up. The first material to use is the substrate. And according to the University Federation for Animal Welfare, the best substrate for goldfish is sand. This is mainly because it’s fine, natural, and easy to clean.

Even so, many aquarists use gravel because it has similar characteristics with sand. It’s also more readily available. Still, you should avoid the pea-sized gravel commonly sold in pet shops as it might choke your fish. Your gravel should be ¾” or ½” in size.

Once you buy the substrate, ensure to rinse it in tap water. This will help get rid of any impurities in the gravel or sand. After rinsing, simply use your hands to pour the gravel along the tank’s bottom, albeit evenly.

Add Plants and Water

When it comes to goldfish tank plants, you can keep two kinds: artificial or live plants. Live plants tend to get eaten, especially if they aren’t the “fast-growth” type. As such, go for plants that will grow fast enough not to get nibbled to death by your goldfish.

Some excellent examples include Amazon sword, Anacharis, Banana plant, Java Fern, Hornwort, Duckweed, Water Wisteria, etc. Once the gravel and plants are in place, you can add the water.

It’s vital to realize that you should never fill your tank with untreated tap water. If you have to use tap water, ensure to treat it with a de-chlorinator. Otherwise, you can buy goldfish-specified water from your nearest pet shop.

When you get the right water, fill up the tank up to a point that’s merely below the wood or black rim. Take note that the water might make a few objects move and you may, therefore, need to reposition them before going to the next step.

Another key point is that goldfish prefer to reside in cooler waters. Therefore, the ideal tank water temperature is between 65 to 72 degrees Fahrenheit, depending on the species of fish you have.

Choose a Good Filter

Without a doubt, the type of filter you use for the goldfish tank can make or break your fishkeeping project. A filter will assist you to get rid of excess nitrates, ammonia and dirt in the tank. Yes, it will go a long way in helping you preserve a healthy, aerated environment within your goldfish tank.

A decent filter will definitely save you some cleaning work, but an excellent filter maximizes your stocking capacity while reducing the number of water changes required to keep your tank fresh. There are many kinds of aquarium filters out there, so take your time to consult and choose carefully.

Add Lighting

Considering that you shouldn’t keep your goldfish in direct sunlight, they will need artificial light to stay healthy and vibrant. So, which type of lighting should you utilize? Full-spectrum lighting.

Because this type of lighting provides Vitamin D for your goldfish’s skin. If anything, Vitamin D deficiency in goldfish may cause them to suffer from muscle malfunction, bone disease, and endocrine disruption.

Therefore, you ought to avoid standard aquarium lighting as it doesn’t fit the bill. It’s better to even go for full-spectrum LED lighting instead. Notably, full-spectrum lighting not only helps your fish grow but also live plants too.

Cycle the Fish Tank

Yes, you can’t put the goldfish in the tank just yet. Cycling the tank is a vital step proper goldfish care and tank setup. So, what does ‘cycling the tank mean?’

As you know, goldfish produce waste just like all other animals do. While this wastage doesn’t pose any risk in the wild, it can be quite a hazard even in large goldfish tanks, no matter how many water changes you undertake. Now, this is where the cycling process comes in.

Cycling simply refers to amassing ‘good bacteria’ in your goldfish tank- mostly in the gravel and filter areas. In essence, these bacteria take your tank’s water through the ‘Nitrogen Cycle’ process, which keeps your aquarium safe for your pets. There are two stages to the Nitrogen Cycle process:

Ammonia turns into Nitrites

The ‘good bacteria’ work on any ammonia in your tank and turn it into nitrites. And just as with ammonia, nitrites aren’t good for your fish. Luckily, the process goes a step further.

Nitrite turn into Nitrates

Thanks to bacteria, the nitrites turn into nitrates. Nitrates aren’t as harmful as nitrites and ammonia. In fact, nitrates get harmful only when they are in large quantities. The best part is that regular water changes can help neutralize the nitrates.

You can cycle your fish tank by simply setting it up as if the goldfish are already in it. This means adding water, plants, substrate and even installing the filter. You can then switch the filter on, before adding ammonia.

The ammonia should get added until the consequent water tests indicate that the tank has zero nitrite, zero ammonia, and some nitrate. Yes, you need to conduct test throughout the cycling process. You can do this using a testing kit.

Take into account that the cycling process may take several days. It’s best to add one drop of ammonia (per day) for every gallon of tank water. After a few days, test the water. The result should indicate a high ammonia reading and some nitrites. If the nitrites are a no show, add ammonia until they read on the tests.

Once the nitrites appear, continue adding ammonia and test for nitrates. Notably, it can take even weeks for the nitrates to appear. When this happens, add ammonia and test for all three substances.

Remember, the tank doesn’t get fully cycled until there is zero ammonia, nitrites, and a high reading of nitrates. If the cycling process seems to be taking too long, here are several things you can do to speed it up:

  • High Temperature – Bacteria tend to reproduce more quickly in warm water compared to cold.
  • Go for bacteria in a bottle – You’ve probably come across bacteria products in many pet shops. While it’s not a guarantee, these products can help you build a bacteria colony superfast.
  • Borrow bacteria – If you have a friend who has already set up their goldfish tank, you can borrow bacteria from them by using some of his/ her gravel.

Finally – Add the Gold Fish

Moving into a new environment can shock any creature, including goldfish. For this reason, you have to take a lot of precaution when adding the fish to your tank. Consider the following pointers:

  • Fish from pet stores usually come in a sealed bag. Take this sealed bag (with the fish inside) and place it in your aquarium.
  • Let the bag float in the water for about ten minutes before opening and adding a cup of the tank’s water in it. Once you’ve done that, seal the bag and allow it to sit in the water for another ten minutes.
  • Repeat this process until the bag gets filled up. After that, use a net to move your goldfish from the bag to the tank.

The above process should allow your fish to assimilate the conditions of the new tank.

Do Goldfish Require an Air Stone?

Also known as an air pump, an air stone works by producing bubbles that break the water surface and add oxygen to your tank. While it’s not a must, adding an air pump will help keep your goldfish tank free from waste.

As you may know, water filters require oxygen to break down waste materials. Whether to add an air pump or not basically depends on the number of fish you’re keeping and how often you conduct tank cleanups.

Do Goldfish Need a Heater?

Heaters aren’t a necessary addition in goldfish tanks because the goldfish species prefer cooler waters. Heating the water will make your pets quite uncomfortable.

That’s unless you live in an extremely cold area and want the tank to maintain specific water temperature.

Can Goldfish Jump Out of the Tank?

Yes, they can. But they will only jump when the conditions of the tank become unbearable or when they are too stressed. For example, you might notice your goldfish attempting to jump out when the aquarium is extremely dirty.

Also, when mating, your goldfish may get over-excited and jump too high, only to end up out of the tank.

How Often to Change Water in a Goldfish Tank?

When it comes to goldfish water changes, it all depends on the number of fish and the tank size.

For instance, if you’re keeping two goldfish, the recommended cycle is a partial change, once every week. For those with busy schedules, changing a larger potion once a month will be fine.


Setting up the tank is one of the most delicate stages of any goldfish keeping endeavor. The environment has to be right or else your fish will suffer.

As such, you ought to ensure that you’ve got the right water, filter, lighting, and even substrate.

Also, ensure to talk with the guys at the pet store before buying any fish. This will go a long way in ensuring that you’re getting healthy goldfish from the off. With that said, happy goldfish keeping.


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