How To Set Up A Freshwater Aquarium

Welcome, you are about to start an adventure to a whole new world. In this article, I will explain how to set up a freshwater aquarium in 9 simple steps.

Adding an aquarium to your home is not only a great way to bring more life and color to your surroundings an aquarium also reduces stress and improves mental health not to mention it’s a feast for the eye.

By taking good care of your aquarium, your fish friends can keep you company for many years. Let’s start by explaining how to set up a freshwater aquarium.

Step 1: Choosing an Aquarium

Before you go all enthusiastic about buying an aquarium you need to think through which size of aquarium you want. Now you might be thinking to take a small-sized aquarium because small-sized aquariums do not take up much space and are cheaper to buy. Which makes this seem like a logical choice.

However, aquariums that are smaller than 10 gallons (37.9 Liter) are actually harder to maintain than a bigger sized aquarium. This is because aquariums that are smaller than 10 gallons (37.9 Liter)will have a faster rise in dangerous ammonia and nitrite levels. It will give you less time to come up with possible solutions to fix your water issues.

Therefore as a beginner, I recommend starting with aquariums that are between 10 and 55 gallons (37.9 and 208.2 Liter) Let’s get to step 2 of how to set up a freshwater aquarium.

Step 2: The Position of the Aquarium Stand

Before you place your aquarium and your stand you need to keep a few things in mind because positioning your aquarium is not only an important step in maintaining the health of your fish friends it will also make it a lot easier for you to do maintenance in, or outside your aquarium.

  • Pick a location that is close to an outlet and allow a few inches/centimeters between the wall and your aquarium to accommodate hoses, filters, cords, and easy access for maintenance. Also, keep in mind the distance for the weekly cleaning of your aquarium. Because you are going to need to haul with water.
  • Position your aquarium in a place where there is no direct sunlight not even for a part of the day. Not only will your plants love it, but the sunlight can also and will increase your algae growth. Which will be a maintenance nightmare for you. Using a timer that controls the light on time is something I definitely suggest.
  • Try to avoid putting your aquarium under or near a vent because it will be a lot more difficult to control a consistent water temperature for your fish friends. Dust will also be blown around if you place your aquarium under a vent.
  • You want to make sure your aquarium is leveled accordingly. Use a spirit level for checking your aquarium if you do not have access to a spirit level you can fill the tank with one or two inches/centimeter water. Check if the water level is an even distance because an aquarium that is unbalanced can be extremely dangerous.
  • Once you have positioned your aquarium and are certain this is the spot you want, you can then add a decoration background sticker.

Step 3: Cleaning the Aquarium

Before you start filling your aquarium with water and decorations you need to make sure your aquarium is clean.

  • Cleaning your aquarium is best with new cloths, that way you are 100% sure there are no household chemicals or maybe other products that could end up in your aquarium.
  • If you bought a new aquarium you just need a damp cloth to wipe off any dust.
  • Be careful if you have bought an acrylic aquarium (new or used). Acrylic is a sensitive form of glass and scratches easily, you will need specific cloths for an acrylic aquarium.
  • Do not ever use soap or other chemicals to clean your aquarium, they are highly toxic to your fish friends.
  • If you did clean your aquarium with soup/chemicals in your enthusiasm then do not panic. All you need to do is rinse, rinse and rinse when you think you are good to go rinse again. That way you are 100% sure your aquarium is clean.
  • With a used aquarium you have to give it a bit more love. Get rid of any debris or dust inside your aquarium. For the inside and outside of the glass, you can use vinegar and a kitchen roll to clean your aquarium.
  • Let’s get to step 4 of how to set up a freshwater aquarium.

Step 4: Cleaning And Adding Substrate

Adding a substrate is very important to keep your aquarium healthy. Not only do you create a nice habitat for your fish friends but some fish like to burrow so they can hide and some like to search through the substrate for bits of food.

You have the option between gravel and sand substrate. Gravel is more suited for beginners because sand substrate will get dead spots if you do not stir on a regular basis, which can ruin your filter.

Talking about filters. if you have an underwater gravel filter you need to install it before adding gravel substrate to your aquarium.

Before you start adding substrate you are going to have to clean it. Substrate comes pre-washed but it will be very dusty and needs to be rinsed.

  • For cleaning gravel substrate you can use tap water to rinse the gravel. Rinse it through with your hands until the water is clean. Do not use soap or other chemicals to clean your gravel substrate.
  • When your gravel substrate is clean you can add it to your aquarium. I suggest starting with a thin layer so you do not scratch the glass on the bottom of your aquarium.
  • For sand substrate, you are going to need a clean bucket. Fill the bucket half-way with water and then add about half a bucket of the sand substrate.
  • While adding sand to the water, swirl with your hand around as it fills.
  • When the bucket is full and the sand has settled, pour out the dirty water and repeat until the water is completely clean.
  • If you got an underwater gravel filter make sure you spread the gravel substrate across the surface of the filter in an even layer.

Step 5: Checking Your Freshwater Aquarium for Leaks

Before you start filling your aquarium you need to check if there are no leaks. Fil your aquarium a few inches/centimeters with room temperature water. To avoid the substrate from stirring you can use a plate or a cup when you add water.

Awesome your aquarium is partly filled, now check for leaks. Is there any water showing where there should be no water, then you need to fix your aquarium or return it. Let’s get to step 6 of how to set up a freshwater aquarium.

Step 6: Installing The Filter, Heater, and Thermometer

A filter in your aquarium is important because without a filter your fish friends will be poisoned by their own waste and that will cause your fish friends to die or develop a disease.

  • Pick a filtration system that circulates enough water for your aquarium. You can choose between an internal power filter, an external power filter, or an underwater gravel filter.
  • Installing your filter depends on the brand. Read the manufacturer’s directions because every brand is different and the installation can vary per brand.
  • Installing an internal power filter is pretty easy to do, assemble all the parts, and hang the filter on the inside of your aquarium. Do not turn your filter on after installation.
  • External power filters are placed on the outside, on the back of your aquarium. Do not turn your filter on after installation.
  • An underwater gravel filter cannot be used with sand or other fine substrates, use gravel substrate instead. You need to place the underwater gravel filter under the gravel substrate and check if everything is hooked up so that the lift tubes can function properly.
  • The air pump has to be strong enough as well for the size of your aquarium. Do not turn your filter on after installation.

Step 6.1: Heater

  • To decide where the heater goes depends on the type of heater. With a submersible aquarium heater, you need to install it as close as you can to the inflow of the filter. A submersible aquarium heater can be placed horizontal or vertical depending on your preference. Do not plug in your heater after installation.
  • Non-submersible aquarium heaters are positioned vertically near a circulation pump or an inlet/outlet filter to ensure your tank is heated consistently throughout your tank. Do not plug in your heater after installation.

Step 6.2: Thermometer

  • Wait approximately 30 minutes before plugging in the heater. This makes sure that the internal thermometer can adjust slowly to the water temperature and the heater does not get overheated.
  • The temperature for your aquarium water should be around 78-82°Fahrenheit / 25-27°Celcius, for the majority of tropical fish, these temperatures will be fine. A goldfish is not a tropical fish and is far better off at temperatures close to 50-72°Fahrenheit / 10-22°Celcius.
  • To ensure your aquarium is heated consistently throughout your aquarium, the thermometer should be installed on the opposite end of your heater.

Step 7: Adding Plants, Decoration, and Water

Now it is time for the most fun part, decorating your aquarium. You can go as wild as you want, just make sure that before adding plants and decorations to rinse every item and plant before adding them into your aquarium. Do not forget to wash your hands without soap.

  • For getting cute little bubbles you need to hook up an airstone. After installing the airstone check if it works, it would be disappointing if your airstone was not working and no bubbles appear.
  • Arrange all plants and decorations in the way you want because you want to keep your hands out of your aquarium as much as possible to reduce stress levels.
  • Plants and decorations are not only for fun you also need plants for functional use. Fish like to hide and plants actually help your fish friends to stay healthy.
  • After finishing decorating and adding plants, you can fill up the rest of your aquarium with water.
  • Make sure you prevent water from running down the cord into your electrical socket. Make a “drip loop”, let the cords touch the ground first before entering an outlet.
  • Wait around 30 minutes before you turn on your filter and heater. When the filter starts, your aquarium’s water level can drop slightly.
  • Because tap water contains a lot of chemicals like chlorine you are going to need a neutralizer. By adding a water conditioner you can dechlorinate your aquarium water. Follow the instructions on the bottle for the ratio.

Step 8: Cycling Your Aquarium

Before you can add new fish friends you need to cycle your aquarium. It is very important for the health of your fish friends. You can add fish to your aquarium before you cycle but it will mean that your fish also undergoes the cycle process and the bacterial level can be deadly.

For this reason, it is better to wait until the cycle process has finished, that way beneficial bacteria can grow to the point they eat the harmful bacteria. Also known as the nitrogen cycle.

  • Before starting the cycle process your water must be clear for 24-48 hours and the temperature of the water in your aquarium has to be stable.
  • To speed up the cycle process you can use a bacterial catalyst. The bacterial catalyst will help with the growth of beneficial bacteria.
  • Remember to keep the light in the aquarium off during the cycle process or else your algae will be insane.
  • Adding live plants is not only a pleasure to look at they are also very beneficial as they will reduce the number of nitrates.
  • A cycle process can take 3 to 6 weeks, maybe longer before your new aquarium is through the cycling process. Basically, it means your aquarium is building beneficial bacteria in your biological filter. Which is a good thing as it keeps your fish friends safe.
  • You can use an aquarium test kit to check if there is still ammonia or nitrates in your aquarium. Also, test the water quality before adding your new fish friends. The pH level of the water should be as close as possible to the water of the fish shop where you bought your fish friends.

Step 9: Adding Fish to a New Aquarium

Congratulations you have made it and you are now ready to add fish to your aquarium. Hold your horses though because you need to do a few more steps before you can add your new fish friends to your aquarium.

How to Set Up a Freshwater Aquarium - Freshwater Aquarium
Freshwater Aquarium
  • Before placing the unopened bag with fish in your aquarium. Dim the lights in your room and turn off the lights inside your aquarium.
  • When you place your unopened bag with fish in your aquarium let the bag float for around 15-20 minutes.
  • If you add your fish straight into your aquarium without letting the bag float, the water will be too cold. Let your new fish friends slowly adjust to the water temperature.
  • Cut the bag open after 15-20 minutes and add an equal amount of water from the aquarium into the bag. Make sure there is 50% water from the fish store and 50% aquarium water in the bag. Do not mix the water from the bag into your aquarium because this could contaminate the water in your aquarium.
  • Let the bag float for another 15-20 minutes in your aquarium and seal the bag to make sure water will not spill out.
  • Remove your fish with a net from the bag and place them gently in your aquarium. Throw away the remaining water from the bag in a sink as long it is not in your aquarium.
  • Make sure that the type of fish you want for your aquarium are compatible with each other because different fish have different needs and requirements.


Thank you, for reading my step to step guide on how to set up a freshwater aquarium.

Even though it might seem like a lot of work to set up a freshwater aquarium. Time will have flown by before you know it and you are all set and ready to enjoy a new underwater world.

If you have any questions on how to set up a freshwater aquarium. Please feel free to leave them in the comment box below and I will do my best to answer them all.

  1. Thank you for sharing all this wonderful information on setting up a freshwater aquarium.  At first glance, it does seem to entail a lot of work to set-up and subsequently maintaining it.  But as you said, having one will definitely add color and life to your living room.

    Typically, the mindset is that the smaller an item is, the easier it is to maintain.  Thanks to your post, we have come to the realization that this is not so for setting up an aquarium.  This may make the decision to start one easier for us.

    More power to you and your website.

    • Agreed yes a tiny small aquarium might seem like less work and easier but it is exactly the opposite, waste and other toxic chemicals will go a lot faster cause of lack of space, for beginners i def not recommend a small aquarium, you might get frustrated cause your fish keeps dying or get sick and it will ruin the hobby for you

  2. This is very fascinating for me, and I totally agree with you about the potential benefits of an aquarium in the home. I have tried to develop one, years ago but with no success. Now I know why my effort was unsuccessful. The soap I used in cleaning the tank must have been the culprit, the fishes did not survive beyond a few weeks and it was very disappointing. I am still interested in building one. This time, by following your instructions, I am sure to get it right. Thanks.

    • Thank you for reading my article and ouch soap yeah that could have been a killer for your fish. Not sure if you cycled your aquarium as well, if not then it is a double dose of toxic and chemicals that your fish have to go through 🙂 I wish you a lot of healthy fish with your next aquarium project 🙂 

  3. This is very interesting for me, I like the way you explained in details….. All along setting up an aquarium has really seemed difficult for me but with this article yours, you have  really made setting up a fresh water aquarium look very simple and easy to maintain.. I’m looking for forward to setting up one soon. But I would love to get a response from you on,  How much it would cost to set up a small aquarium? 

    • Hello, thank you for reading my article 🙂 How many gallons(liters) are you thinking about? Because the amount of money can vary a lot per set up. For a 25-30 gallon(94-113 liter) aquarium for example you are gonna need around 400-600 dollars.

      You need to buy equipment like a stand, substrate, decorations, plants, food, the actual fish themself, driftwood/rock, medication, a net, algae scraper, ammonia test kit, chlorine reducer and some more ^^

      Which can all add up in the price cost.

  4. Wow I like your idea of cleaning of the aquarium, it’s innovative. Since I was a child I always wanted to own an aquarium. I always admired it from afar. I  have one very little aquarium at the moment but I am thinking of getting something of at least three feet square. Now I know some ways to go about taking good care of it. Thanks very much for this very revealing article. You guys have done a really good job here. Thanks once again. 


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