What Is A Brackish Aquarium?

Setting up a new aquarium can be very exciting. It is important to do your homework though before you start. You should start with what type of fish you want to raise. This will lead you to what type of aquarium your fish needs to live in. Not all fish can live together. Also, most people starting out know about fresh and saltwater aquariums, but did you also know there is something called a brackish aquarium?

What is a brackish aquarium?

For those who don’t know, a brackish aquarium is an aquarium that contains brackish water (semi-salty). It is basically a mixture of freshwater and saltwater. They are easy to maintain since the fish from brackish waters are designed to withstand frequent salinity and water parameter changes unlike both fresh and saltwater fish

So, if you feel it’s time you made a change from purely freshwater tanks, and you’d like to try out a different pattern of fish-keeping without committing to a full-time marine set-up, then a brackish aquarium might be just what you need!

Or if you are just starting, a brackish aquarium may be a perfect fit since they are easier.

Brackish aquariums have a significant advantage, being that they are very easy to maintain. This because the inhabitants can adapt to different water pH and salt levels.

Now you may be wondering how to set up a brackish tank, well keep reading, because I will be giving you all the info you need!

How to Set Up A Brackish Tank

You can use any size of tank for your brackish aquarium set-up. However, this depends on the size and number of fish you are planning to buy.

There is a wide range of brackish species that have high levels of adaptability, so you can explore your options.

As a rule of thumb, brackish tanks should contain hard water with a pH level that ranges between 7.2 to 8.5. It should also have a specific gravity of 1.005 to 1.020.

As for the temperature of the tank, a range of 23 to 29°c will do just fine. Although, to maintain such temperatures, it is required that you install a heater in your tank.

Keep in mind that you are to add the salt mixture and water in a separate bucket before pouring into the tank.

There is a reason for this: Adding salt water directly to the tank can be harmful to your fish, and to your plants as well.

It is recommended that you use about 10 grams of marine salt per liter of water.

Filing the Tank

  • Add fresh water to a bucket but leave some space at the top for rising levels from the salt.
  • Use a heater to make the bucket water temperature the same as the temperature in the tank
  • Gently add the appropriate amount of salt for the amount of water in the bucket
  • Stir the saltwater
  • Let the mixture sit for 20 minutes to ensure all the salt has dissolved
  • Stir the water again

Remember to continuously measure the specific gravity with your hydrometer as you pour water into the tank. Do this until you get the right levels.

After 7 days, the nitrogen cycle would have been completed. At this time, you can add the fish into the tank.

If it so happens that you want to switch from a freshwater tank, then switching the water type should be done patiently. This could take 2 to 3 weeks.

Take out about 20% of the water, then replace it with your saltwater mixture, and increase the specific gravity levels by no more than .002 per week.

By doing this, your fish can slowly adapt to the water changes being made, therefore they would not be harmed.

What You Need for Brackish Tank Care

It is vital that you have a thermometer, also a hydrometer or a refractometer. You will use these to measure the temperature and specific gravity of the new water.

Also, the type of salt you use is worth considering. I recommend you go with a marine salt mix, instead of an aquarium salt mix.

It would be a terrible idea to use table salt, as it contains silicates and iodide.

Make sure all the equipment you use is ideal for both saltwater and freshwater aquariums. If you use equipment that is specific to freshwater, then they could be damaged by the salt. Keep this in mind when choosing heaters and filters.

Gravel and pebbles can be used in brackish tanks to cover the tank floor. They are common in natural brackish habitats, so they’ll work just fine.

You can also buy driftwood or tree ornaments for the tank, as they would make your fish feel like they are in their natural habitat.

Brackish Fish Species Appropriate for Your Aquarium

Naturally changing environments are not strange to brackish fish, as they are already used to it. They would do well with gradual changes in salt and pH levels.

Shrimp, Black Mollies, and Bumblebee Gobies are ideal species for your brackish tank.

Brackish Tank Maintenance Schedule

You need to have a maintenance schedule for your new tank.

You should change about 15% of the tank water once a week.

You should also clean the tank floor by using your fishnet to stir up the stones and pebbles, then scoop up any floating debris.

Then, you make another saltwater mixture in a separate bucket, then use it to replace the 15% water you initially took out. This should be done after the salt has dissolved in the bucket.

Besides the weekly water change, observe your water salinity levels on a daily basis, because water evaporation will leave some salt behind, and make your aquarium saltier than you or your fish would care for.

Give your tank a deep clean at least once in a month. This will involve cleaning the glass and other ornaments in the tank, as well as a filter change.

By following these brackish tank set-up steps and maintenance routines, your fish and aquarium plants will remain happy, and they will thrive in their new environment.

Remember that not all brackish fish are the same, they come in different shapes, sizes, and behaviors. For this reason, be sure to buy a tank that is right for the size, and the number of brackish fish you plan to buy.

Some Brackish fish love to play, so you can buy some ornaments and scatter around the aquarium floor. Their happiness is key to enjoying their new home.


I trust your question – What is a brackish aquarium, has been answered by this article.

Remember to follow the best maintenance practices to get the most out of your brackish aquarium.

Take care!

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