Can a Saltwater Tank be Used for Freshwater?

Can a Saltwater Tank be Used for Freshwater?

Here are the best DIY methods for converting a saltwater tank to a freshwater aquarium. We have also added the Pros and Cons for saltwater and freshwater tanks.

Can a Saltwater Tank be Used for Freshwater? You can turn your saltwater fish tank to a freshwater, through simple steps of cleaning and assembling. A saltwater fish tank is difficult to maintain as you have to put constant effort into the fish and environment maintenance. Also, you need to search a lot about saltwater fish and plant nature otherwise you can cause harm to them. So, when you do not have sufficient time and expense to spend on your saltwater aquarium, change it to a freshwater aquarium.

Can a Saltwater Tank be Used for Freshwater?

If you want to convert your saltwater aquarium to freshwater, follow these steps to easily convert it to freshwater without causing any damage to the animals.

Aquariums are the best addition to a home as they beautify the home aesthetic and creates a beautiful aqua-space. You can choose a saltwater or freshwater water fish tank as per your desire and convenience. Both look stunning and brightens up the area wherever you place it.

When you decide to change it, think carefully to find a safe home for the saltwater fish and plants as they can not survive in freshwater. Once you find a safe place, shift them to their new home and prepare and refurbish your aquarium.

Your freshwater tank is incomplete without a plant, and it is also known as a planted tank. You can add many plants to enhance beauty, and these plants help reduce algae growth.

Saltwater plants are harder to maintain, and they do not reduce algae, so you have to keep cleaning equipment such as protein skimmers. Also, you have to search thoroughly for the correct selection of plants.

Difference between the saltwater aquarium and freshwater aquarium

Saltwater aquarium

Saltwater or marine fish tank contains a specific salt level, and certain fish and plants can survive in this environment. You can add many colorful fish and other interests to it to makes it look stunning and gorgeous.

It is challenging to maintain and establish and requires more filtration. You can not include any ordinary plant in it; corals and anemones are suitable for it.

Freshwater aquarium

A freshwater or tropical fish aquarium is easy to operate and maintain as it does not require too much effort. You do not have to think so much about the selection of plants and fish for it.

You can see them swimming and playing across clear and clean water, which serves as a beautiful display to the eyes. Also, you can add invertebrates like a snail and cory cat to manage the algal growth.

How to convert a saltwater fish tank to a freshwater tank?

You have to be very careful while converting it as a little carelessness can harm fish health. You have to replace the filter, substrate and remove all the wastes or residues completely before adding freshwater. 

Just disposing of the saltwater and pouring in freshwater is not enough; you have to clean every corner or edge to remove all residues. Here are simple steps for cleaning and converting it to a freshwater tank

Cleaning of the tank

Emptying of the aquarium

The first step is the remove everything from the tank and empties it. Shift all the fish and other animals to a safe place, then remove all the plants from it. You can not add saltwater plants to freshwater, so keep them with the saltwater fish or discard them. You can make a wooden fish tank stand at home and use it.

Now remove all the equipment such as filter, heater, lights, powerheads, and others. You have to discard the sand and substrate because you can not use this coral sand in a freshwater tank as it is not safe. 

If you have accessories in it, either discard it or clean it properly to place in freshwater. Now drain the water with a pump or pipe that will drain all the water to the disposal area. 

Clean filter

Next, you have to clean your filter, and for this, discard the filter pads and clean the filter carefully. Add a new filter sponge, filter floss, or charcoal, and your filter is ready for the freshwater setup. You can use bio balls or any other similar thing to help the beneficial bacteria grow in your filter.

Clean and scrub the tank

Rinse the tank properly with plenty of water and clean every corner of it. Better to scrub to ensure cleanness and safety and for this, prepare a mix of 1-gallon water and 1 cup of vinegar. Take a sponge and scrub off contaminants from the entire surface and glass with this water-vinegar mix. 

Vinegar is safe and removes hard water scales, Coraline algae, and other deposits, and does not harm animals. After scrubbing all the sides and corners of the tank, rinse it thoroughly to wash out all the mix. This is a must otherwise, your aquarium can leak water.

Clean accessories

If you want to use accessories from the saltwater setup in the freshwater:

  1. Remember to clean and sterilize them before placing them in the tank.
  2. You can use a bucket filled with water and add a small amount of diluted bleach.
  3. Submerge the accessories in the bucket for at least an hour. 

Do not add other chemicals, as only bleach is enough to clean it. After an hour, remove accessories from the bucket and rinse them thoroughly with cold water. If you still have any doubt, sterilize them by placing them in boiling water for half an hour.

Assemble the freshwater tank

Install background

Adding a background provides visual depth and a more aquatic feel to the tank. It also conceals the equipment behind and gives a homely feel to the fish. Attach the background wallpaper using tape or hooks on the outer backside of the tank. Many people like to make a blackwater aquarium at home.

Add gravel

After attaching the background, add gravel into it, but make sure to rinse the gravel first with water and colander to disinfect it. Substrate gives a place for beneficial bacteria to grow and live. These bacteria help in filtering the water and provide biological balance to the aquarium.

The fine medium-sizes grain is preferable for small fish and coarse gravel for large fish that like to dig in the substrate. The color should be a little dark to hide all the dirt and wastes. Correct selection of gravel is necessary to ensure plant and fish health as it acts as a substrate for them. 

Add decorations

Adding some decorative pieces in an aquarium enhances the beauty and provides a place for fish to hide and play. Fish feel more safe and secure when you add these little objects and place the fish tank in your home.

You can add beautiful stones, some toys, and a mini home but remember all these objects should be safe for the fish. It is better to rinse them first or sterilize them by submerging them in boiling water for a while.

Add filter and heater and fill the tank

Attach and assemble filter of appropriate size as it is an essential equipment of an aquarium. Do not plug in or start it at this time. Now add a heater of a suitable size and set the temperature between 75-80 degrees Fahrenheit. 

Fix the heater near the filter inlet or outflow for the proper distribution of heat. As you have to submerge the heater in the water, so place it horizontally for even heat distribution; do not plug-in yet.

Fill half of the tank with room temperature freshwater or tap water and place a plate or saucer while pouring water to avoid disturbing gravel.

Add plants and driftwood

Now it is the time to place artificial plants and driftwood into the tank but do not forget to clean and sterilize them well. Do not place live plants until you run your aquarium for at least 48 hours.


It is not always necessary, but better to add an aerator in the tank for maintaining dissolved oxygen level, and it also helps in biological filtration. You can incorporate an air diffuser in decoration pieces but do not place it near the filter inlet as it may block the filter if air draws in the filter.

Water conditioner

A water conditioner is essential for softening water as the tap water may contain chlorine and heavy metals, which are harmful to plants and fish. Use a good quality water conditioner that efficiently neutralizes these chemicals, or you may use other conditioners of your choice.

Plug-in filter, heater, and fill the tank

Now plug in the heater and filter to maintain water temperature and quality and let them work. Fill the rest of the tank and cover the tank but do not overload. Lit all the lights and wait for 24-48 hours for the stability of tank conditions.

Add fish and live plants

Wair for 24 to 48 hours, when the water temperature becomes stable, and after the cloudiness dissipates, add your fish and plants. First, add small fish to initiate the nitrogen cycle, and then add all big fish, other invertebrates, and your live plants.

Pros and cons of the saltwater tank and freshwater aquarium

Cost of maintenance

The freshwater setup costs less as compare to saltwater as the plants and fish are reasonable. You do not need to make a large tank as a ten-gallon tank is enough. Also, its maintenance does not require a lot of money and expenses as it does not require too much equipment.

The saltwater is more costly and expensive to install and maintain as it requires more equipment for the setup. You can not compromise on the filter, protein skimmer, powerheads, hydrometer, gravel vacuum, and others. The fish and livestock for saltwater are considerably higher in cost. 

Beginners friendly

For beginners, a freshwater tank is better, as it is more friendly and easy to maintain. Basic knowledge is enough to establish it, and the fish and plant for the freshwater tank can adapt to environmental changes. Do not worry about the stability of the tank because you are using tap water. 

A saltwater aquarium is too hard for novices as you have to get a lot of knowledge about the inhabitants. You can not take any fish or plant and place them in it without any information about their behavior and habitat.

Also, it requires a specific environment, and you have to maintain pH, salinity, chlorine level, and other parameters. A consistent and stable environment should be there for dazzling fish, corals, and crustaceans.

Time requirement and workload

The freshwater tank does not require too much time and effort as the animals can adapt to changing conditions. When living as wild, they go through floods, droughts, and other environmental changes.

So they adjust themselves according to fluctuations in the chemical makeup of the environment. Due to this behavior, you do not have to pay too much attention and time in taking care of them.

Saltwater tank requires a high level of care and commitment due to the behavior of its inhabitants. The fish and plants need more amount of attention and time of care. Also, you have to provide constant care to prevent algae growth.

Types of fish for the saltwater tank and freshwater

You can add so many beautiful fish to a freshwater tank including, betta fish, angelfish, cherry barbs, platys, danios, cichlids, plecos, Kuhli loach, and many others. All these fish are not difficult to handle and, you can add snails that reduce the cleaning time of the tank.

Saltwater fish are yellow tangs, bi-color blennies, clownfish, mollies, watchmen gobies, blue damselfish, others. There are comparatively low-maintenance fish than other saltwater fish, and they require less care in comparison. Otherwise, saltwater fish require extensive care and time.

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