Everything You Need To Set Up A 20 to 25-Gallon Aquarium Tank

aquarium with multiple aquatic plants

A 20-25 gallon tank is the perfect starter aquarium size. Contrary to popular belief, larger tanks are actually easier to maintain than smaller aquariums. So, if you’re setting up a tank of this size, take some time to read our list of eight items you need to set up a 20-25 gallon aquarium.

Aquarium Stand

After you’ve chosen your 20 to 25-gallon tank, you will want to choose an aquarium stand that can support the tank and meshes with the decor and space of the room in which you will setup the 25-gallon fish tank. You’ll want to place the tank and stand away from direct sunlight, windows, and air vents or radiators.

Filtration System

Next, you’ll want to decide if you want an canister or hang on the back power filter. The latter is recommended for beginners since it’s easy to set-up, use, and clean. For a 25-gallon fish tank setup, you need a power filter capable of filtering 125 gallons per hour (gph).

Gravel or Substrate

Beginners should use gravel to keep a healthy aquarium. In lieu of gravel, more advanced aquarium owners can choose sand, crushed limestone, and other types of substrate for fish and other animals that like to burrow. If you do go with gravel, remember to keep it clean and make sure to rinse it thoroughly and slowly pour the gravel to let it settle and use the filter to clear any dust in the water.

Plants & Decorations

Adding live plants to an aquarium helps any tank look more appealing, but this also serves a biological purpose as plants filter water and can improve the health of any fish in your tank. In a 20 to 25-gallon fish tank setup, you will want to set-up plants and decorations before adding fish, to make the transition for the fish as stress-free as possible. Rocks and driftwood also make great additions to aquariums, and can act as anchors for live plants.

Water Heater

Different fish are bred to survive a variety of temperatures and environments. To keep a constant temperature, you may need to use a water heater. Once the tank is full, the heater can be turned on and kept between 78 and 82 degrees (Fahrenheit) for a community tank. For beginners, look for fully-submersible heaters as they are the easiest to use.

Water Dechlorinator

If you are filling your 20 to 25-gallon fish tank setup with tap water, then you will need a water dechlorinator to neutralize the chlorine and other chemicals in the water that are dangerous for the fish you will put in the tank. This is not necessary if you decide to use distilled water in your aquarium.

Test Kits & Ammonia Remover

Before adding any fish in the aquarium, make sure to cycle the tank for at least a few weeks to grow beneficial bacteria. This process is called the ‘fishless cycle.’ During this period, you should monitor the water for different conditions (pH level, ammonia level, along with nitrite and nitrate levels). Once these levels are balanced and conducive to sustaining fish and plant life, then you can start introducing both to your tank.


Once you have all the elements above for your aquarium setup, then you are ready to add fish. Choose freshwater fish that are known to be compatible and non-predatory to one another. Be patient and make sure to do your research before adding fish to your aquarium.

For Your Aquarium

At Complete Aquatic Systems, we specialize in many organic and decorative elements that customers need for a 20 to 25-gallon fish tank setup. We started as a family business over 17 years ago, and we are happy to help you provide your customers with all of the essential plants and decor needed. To inquire about our complete catalog of aquatic plants and decor, contact us today.