How to Set Up a Fish Tank [Simple Steps]

New fish keepers, welcome! For anyone looking to start keeping fish, there are a few things you need to know first. While a fish tank is a beautiful addition to any room, it has to be properly prepared and maintained.

There is a lot of planning that goes into running an aquarium, so you want to be well prepared and informed.


A Few Things to Know Before You Begin

Before you do anything, you must know that you cannot put fish straight into a new tank. The bacteria levels need to be established, there can be no harmful chemicals in the water, and there must be sufficient filtration.

We will come back to that later but for now, just know that the process of conditioning your tank takes about 3 to 6 weeks, and it should not be overlooked. If the tank is not properly conditioned, it could kill all the fish that enter it.

Be aware of the maintenance your tank is going to require. You will have to do regular water changes and tests so that the water is clean, well balanced and free of harmful chemicals. Failure to do so could lead to your fish getting diseased and ultimately dying.

Remember, these fish are your pets. They rely on you for completely for their survival. It is your responsibility to keep their environment clean, healthy, and safe.

Choosing A Tank Location

Before you purchase a tank, you need to know where you’re going to put it. Once you have your tank set up it will be extremely difficult to pick it up and move it somewhere else, so you want to be sure it’s in a good spot before you fill it.

Most importantly, you need to put it somewhere in plain sight. That way you can fully enjoy it, and if anything goes wrong, you can spot it quickly.

You will also want it to be near a power outlet and water source. The filters, heaters and lights need a power source, and to make tank maintenance easier you will want to be near a water source.

You don’t want the tank to be too crammed because you need to be able to access the top for feeding and water changes. You also want to be able to comfortably perform maintenance on the tank.

Make sure your tank is on a secure surface, your tank will be pretty heavy so you need the table underneath to be strong enough to support it.

Too much natural sunlight hitting your tank will lead to a build-up in algae. Algae will block your fish and make the tank look less attractive. Don’t put it too near to windows.

Be aware of the temperature in the area of the tank, it can drastically change the temperature inside the aquarium. Don’t put your tank near heaters, fireplaces, fans or air conditioning vents. Changes in temperature in the water can put your fish under severe stress and even lead them to get sick or die.


Choosing Your Tank

When choosing a tank, it may be tempting to go with a smaller one. However, this can actually be a more difficult size to manage for beginners. With a small tank, water levels change very easily and quickly so you have to be experienced enough to fix the slightest changes.

You will want to choose a tank that is over 20 gallons so that there is more room for mistakes to be made.

For a tank under 150 gallons, choose a glass tank. Glass tanks are cheaper, easier to find, and don’t scratch as easily as acrylic ones, they’re the best choice for beginners.

Bigger tanks are going to be more expensive, and aquariums are expensive to maintain, so be sure to have a financial plan. If you’re on a tight budget consider getting an aquarium on the smaller side. The more water in your tank the bigger the filter and heater will have to be, and the more water conditioner you will need. The costs will add up.

Another important factor when choosing a tank is how big the opening of the tank is. Fish need oxygen in the water in order to survive, and oxygen will enter the water from the surface. The size of the tank surface is going to limit how many fish you can have in your tank. Always choose the tank that has the larger water surface.

Don’t over face yourself: choose a tank that is in your budget, works well in your living situation, and is going to be easy for you to manage and maintain.

Choose your tank first and then decide what fish to add in based on your tank.

Choosing Your Fish


Remember, you can’t add your fish yet, but you will want to know in advance what fish you are going to add.

Always research the species of fish you are thinking about adding to your tank so that you ensure they are compatible with your tank and with each other.

Different types of fish are going to have different water, space, equipment, plant and decoration requirements.

Some fish species don’t get along and they can become aggressive with each other. Or, one fish might have completely different water needs to the other.

Be sure to not overstock your tank. The general rule is to have one inch of fish per one gallon of water.

The amount of water in your tank will be less than you think once you have added gravel and decorations.

A 10-gallon tank will hold more like 8 gallons of water. It’s good to be cautious and go under than maximum rather than over when judging how many fish to add to your tank.

Clean Your Tank

Now that you’ve purchased your tank, it’s time to get it set up!

The first thing you need to do is make sure the tank is clean, especially if you have bought one that’s pre-owned. Don’t use any soap or detergents as they may contain harmful chemicals.

Use a cloth and warm water to wipe down the tank and remove any dust. Check there are no holes or scratches on the tank where water can leak out.

Once clean, place the tank in its chosen position. Make sure it is secure and sturdy.

Placing Your Substrate and Ornaments

You will need to choose what substrate and ornaments you use based on what fish and plants you plan on putting in the tank.

Make sure to research your fish thoroughly so that you can make them comfortable.

It is essential to clean your substrate, rocks and any ornaments before putting them into the tank. Cleaning them removes and dirt and dust that would otherwise cloud up the tank and effect the water quality.

Pour the substrate, rock and ornaments into a bucket and then spray them with high pressure water. Stir them around and drain them. Keep washing them until the strained water is clear.

Once clean, you can add the substrate, rocks and ornaments to the tank. Make sure the substrate is evenly spread throughout the bottom of the tank. Smooth it with your hands so that the base is even.

You should place a minimum of about 2 inches of substrate, but it depends on the size of your tank. Again, be sure to research your specific tank and fish needs.

Place the rocks and ornaments in evenly distributed spots in the tank. That way your fish have plenty of areas to explore.

Filling the Tank with Water

Freshwater Tank

Before you fill your tank, place a saucer or a plate over the substrate so that it doesn’t disperse around the tank. Fill the tank about one-third full of room temperature water.

Next, add the water conditioner or dechlorinator. Chlorine in the tank can be deadly for your fish so it is essential that you complete this step.

The water may turn cloudy in the next couple of days, this is due to bacteria growth and is normal. It will disappear naturally.

Saltwater Tank

If you are planning a salt water tank, you should process the water through reverse osmosis.

You can buy water that has been through the reverse osmosis process, or you can purchase filter systems that will do it for you. They can be expensive so if you have to, you can use tap water and put in a high quality dechlorinator.

Next, you need to add the salt mix. You can purchase salt mixes from most pet stores. Follow the instructions carefully so that you add the right amount.

Add the water to the tank in the same way as the freshwater, again placing a saucer over the substrate.

Adding the Filter and Heater

Filtration for a tank is extremely important. There are three necessary stages: mechanical, chemical and biological.

Be sure to find an efficient filter as it is vital to the aquarium’s health and cleanliness.

Your filter should pass all the water from the tank through it at least 3 times in an hour. If it doesn’t then it may be too small. You need to choose a filter that will be able to adequately filter all the water from the tank.

It is best to get a bigger filter. Over filtering is no problem, but under-filtering is. Your fish health depends on it.

Follow the instructions carefully to ensure you fit your filter properly to the tank. It needs to be in the right position so that it can properly reach the water and spit the water back out.

Heaters are required for saltwater and tropical tanks. You want to choose heaters that comfortably fit inside the tank. Most tanks need two heaters but smaller tanks can get by with just one.

Follow the instructions carefully on your heater so that it is properly fitted to the tank. Be sure to monitor the temperature of the water with a thermometer.

Lights and Air Pump

Adding lights is essential for the happiness of your fish and plants. It provides a source of day and night for your fish to engage in their natural sleep patterns.

Choose a light that works well with your tank and place it on or above your tank. You can put it on a timer so it’s on for 8 hours a day and turns off automatically.

Air pumps are important for fish tanks because they ensure that your fish are getting enough oxygen. Connect your air pump to an air outlet in your tank, such as an air stone. Follow the instructions carefully so that your air pump is properly installed.


Plants are a great addition to any tank because they provide more oxygen to the water. They also make great hiding places for your fish.

If you are using live plants, you will have to research what type of substrate they need. Fake plants can be great for décor, and they create hiding places around the tank for your fish.

Place your plants in the desired positions, and spread them evenly throughout the tank so that your fish has plenty of hiding spaces. If you are using live plants, be sure to research where they like to be placed. They have different needs.

Cycling the Tank

Now that you have made it this far, you’ve reached the most important step, cycling!

Nitrogen cycling is the process where bacteria and plants convert and consume nitrogen from their environment. animals then eat those bacteria and plants, and then plants and bacteria consume their waste. This is a vital process to create a healthy ecosystem. But, in a brand-new fish tank there are no good bacteria to break down the fish waste. When you perform an aquarium cycle, you make sure that the tank’s ecosystem processes ammonia without killing any of the fish.

A lot of the time, aquarium cycles are performed with the fish in the tank. However, it is better to cycle the tank without the fish present so that they aren’t exposed to any harmful chemicals.

Freshwater Cycling

Add about 2-4ppm of ammonia to the tank to begin with. Then you will add small additional amounts over the next few days. Follow the instructions on the bottle carefully.

The process should take about 2 to 8 weeks. Once the ammonia and nitrate levels are at 0ppm, you can add your fish. Having increased water temperature or an air pump will help to speed along the process.

Saltwater Cycling

The best way to cycle a saltwater tank is to use a live rock or live sand. The rock comes from the ocean and has dead bacteria living in and on it. When it is transported back into the water the dead bacteria start decomposing, triggering a nitrogen cycle. This produces ammonia and the cycle begins.

The process takes about 6 to 8 weeks. Once the ammonia and nitrate levels are at 0ppm, you can add your fish.

Adding Your Fish

Normally your fish will be transported using a plastic bag filled with water. Try to keep the fish in a dark place so that it stays calm and comfortable.

Try to get the fish home as quickly as possible. You will need to get the fish into the tank quickly so that it’s stress levels are lower, and it is able to acclimate to the tank more quickly.

If you are concerned your fish might be diseased, you can quarantine it in a separate tank before entering it to the main one.

Dim the lights in the tank before entering the fish. This will also help to lower its stress levels.

Place the fish in the unopened bag into the tank. Let it float around in there for about 15 to 20 minutes, this will give it time to get used to the water temperature.

Then, open the bag and pour some of the tank water into the bag. The fish should be sitting in 50% pet store water and 50% tank water. Be sure to not let pet store water into the tank so that it doesn’t contaminate it.

Seal the edge of the bag and let it float for 15-20 more minutes.

Then, net the fish out of the bag and gently into the tank.

If you added plants, rocks and decorations to your tank, your fish will enjoy being able to have some hiding spots.

Monitor your fish for any signs of disease or stress. If there are other fish in the tank, make sure they are all getting along peacefully.


Hopefully you feel ready to own your own fish tank! The process may seem long and complicated, but it is worth all the effort. At the end of all your hard work you have a beautiful little ecosystem and you can watch it grow and flourish.

As long as you put plenty of time into planning your tank, research thoroughly everything that goes into it, and maintain it carefully, you won’t have any issues.

Good luck!

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