Important Things to Know When Setting Up a Freshwater Aquarium (Guide)

Over the past several years fishkeeping as a hobby has grown tremendously in popularity, with many people from all over the world taking the plunge in becoming an experienced hobbyist. For most, starting a home aquarium with no prior experience is a rather daunting task, and requires some careful considerations.

Typically, you will be advised to start a freshwater aquarium first, before going into saltwater aquariums and managing saltwater fish, this is due to it being slightly less maintenance, cheaper, and more accessible in terms of options from local pet stores of fish keeping shops.

Something many people tend to overlook when choosing an aquarium is the size of the fish, they expect to house in it. Certain fish thrive and others will do very badly if they are restrained to a certain sized fish tank. The Lionfish Lair website has plenty of good information about fish and their tank requirements.

We will be discussing and taking you through the most important things to know and consider when you are setting up a freshwater aquarium for the first time, or perhaps are going from a saltwater tank to a freshwater tank. Let’s dive in!


Before you do anything regarding setting up your freshwater aquarium you must consider the location. Many people overlook this, end up purchasing a tank and fish and then have absolutely no idea where a suitable place to keep them is. And by suitable, we don’t just mean in terms of the best lighting, or height to view your aquarium fish community, we mean a safe place for your new freshwater fish to live a happy and healthy life.

Your tank should be situated away from windows, outside doors, heat vents, and air conditioners. This is because fish become incredibly stressed when they are exposed to rapid temperature changes, and stressed fish is never good. Additionally, sunlight exposure may make your tank look amazing for the first couple of days, but after a while your tank will become infested with green algae that will make it hard to even identify your aquarium freshwater fish.

In some circumstances, apartment rental agreements will limit the size of your aquarium, so make sure to check up on how big a tank you are allowed to have. Also, you should certainly keep your tank in a room where you spend a lot of time in, and make sure that there are at least 3 electrical outlets nearby where you want to place your new aquarium. Fish tanks are not light, in fact, water weighs around 8 lbs. per gallon, so you need a secure place to situate your tank so that it can handle the weight!

Tank set up

When you first purchase your tank, whether it is second-hand, or brand new, you need to give it a thorough clean, making sure it is almost spotless before the next step is taken. Next you will need to make sure that the tank itself is on a level and stable surface.

You can purchase tank stands online or in store and also can create your own if you have the right tools and equipment. If your tank is not level, it can be incredibly dangerous, increasing the risk of leaks and cracks too.

You must also make sure that there is enough space between the wall and the back of your aquarium so that you can easy access the filtration units and also the plugs and sockets behind the tank. Talking about filters, the next step will be to install your water filter, to do this, simply follow the manual you received with your tank and filter.


Once you have acquired substrate, rinse it out and disinfect it using a kitchen colander (or similar), the same goes with your tank décor. After this, place the clean substrate and decorations into your tank.

Beneficial bacteria begin to form on substrate as your tank becomes more established, a good idea is to purchase some substrate from an existing aquarium that contains these beneficial bacteria and add a couple of cupsful to your own.

Add an air stone

This next tip isn’t crucial, although it will benefit your tank and fish community tremendously. An air stone produces many bubbles that are great for cleaning the tank water and making sure it remains fresh when you are not due to clean it. The bubbles produced are even known for benefiting your tanks water to the point of helping prevent fish diseases, and more.

Fill up your tank

If you haven’t discovered any leaks in your new tank and everything else is up-together, then fill up your tank with the rest of the water. In order to protect your newly acquired décor and substrate, place a small bowl in your tank and then pour the water directly in your tank with the required additive.

Tank Heater

Place your heater into your tank, however, do not plug it into the socket yet. The best location for the heater really does depend on the type of heater you are using. With the clip-on heaters, you must hang them vertically in your tank and they must be placed close to the outflow filter.

If you are using a submersible heater, then you should place it as close as possible to the inflow of the filter in your tank. These placements are great for your tank as they will allow heated water through your heater to be dispersed throughout your tank.

You must wait around 20 minutes to plug in your heater after you have added it to your tank. Doing this will ensure that the heater doesn’t overheat whilst adapting your thermometer to the water temperature. Your heater will typically include instructions for this within its manual, but you will want to adjust the water temperature to your tanks needs, which is usually around 75F, about 24 Celsius.


When you install your thermometer, it is incredibly important to read carefully whatever instructions are in the manual for it. The thermometer should be on the opposite end of the tank from where the heater is, and in a position which is easy to see and gauge.


After you have completed these steps, you will want to wait at least 24 hours, however 48 is the recommended amount before you start to add your freshwater fish for aquarium. This will allow your tank to settle and acclimatize to all of the new changes you have made.

You have to give everything time to settle and stabilize before anything else is done. If your tank water is cloudy at first, then wait until it has gone and the tank is clearer before you add your fish, even if this takes you past the 48-hour mark.

Now, if the water temperature in your tank has remained stable for 48 hours and the tank is no longer cloudy, you are ready to start cycling your new tank. You will need to add the additives necessary to speed up the nitrogen cycle. For this, check out a guide on nitrogen cycling in new tanks, to make sure you are doing it right.


In conclusion, getting a new freshwater fish tank for the first time is incredibly exciting and an all in all enjoyable process. However, the fun won’t last if you haven’t correctly set up your tank, leading to all sorts of early issues that could see your community diminished before it has a chance to flourish. So, take your time and take good care when following these tips and you will have a freshwater aquarium teeming with life before you know it.

Krystal Morrison

I create this blog to share my daily tips about home improvement, children, pets, food, health, and ways to be frugal while maintaining a natural lifestyle. Interested to be a Guest Blogger on my website? Please email me at: [email protected]

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