Setting Up the Brackish Water Fish Tank

Setting Up the Brackish Water Fish Tank

When you are first setting up your guppy aquarium most likely you are going to go with the standard fresh water set up. There are some guppy enthusiasts that like to take it a step further and create a environment more like the natural habitat that the guppy breed was originally used to. This is setting up a brackish tank.

While it may sound a little overwhelming it really is not that difficult as the brackish water is comprised of part freshwater and part salt water. The reason that some individuals go this route is because the natural habitat of the guppies was in the swamps and the water in these areas was considered brackish. It takes a little bit of work to set up the tank and to maintain it but many find it well worth it.

You will have to start by finding the proper aquarium that will allow for the addition of the salt water. Glass and acrylic aquariums do work well with this but you want to stay away from any tanks that have metal frames or thermometers, or anything that could be affected by the salt. You will also need to have a hydrometer that allows you to measure the gravity that will be in your tank.

Even though you are doing a brackish set up you still have to be cautious of the tap water that you are going to be adding to the tank. Many times tap water is treated with chlorine and you will need to treat the water for this. Make sure that you condition the water that you’re going to be putting into the tank before you add any salt.

The type of salt that you are going to be using has to be a special salt called Marine Salt. You do not want to use freshwater aquarium salt or your regular table salt for this setup. You should be able to find that you have a selection of Marine Salt at your local fish supplier.

Once you have gotten the right salt you can look at the directions that are on the package, and you will need to stir the water until the salt has fully dissolved. This can take a little time to do as it will depend on the amount of water that is being treated with the salt and its temperature.

For a brackish water fish tank the gravity is going to be really important as this makes sure that you’ve added the right amount salt. This is why you are going to need the hydrometer to give you the reading. The density of brackish water will range between 1.003 to 1.010. Guppies are most happy with brackish water that is close to the lower end of these figures.

You will also want to know what the pH of the water is and guppies can live in water that is comprised of pH between 6.8 to 7.6 but they are happiest when they are in the range of 7 to 7 .6.

One thing that you have to keep in mind about setting up your brackish tank that not all fish will be able to tolerate this type of water set up. So you’ve got to plan for the future as to what you’re going to be adding to this tank.

Also remember that you don’t want anything around the tank that is metal as it will be corroded by the salt. If you are switching a freshwater tank over to a brackish water tank do this slowly in stages by replacing approx.25% of the tank water each week until you’ve reached the gravity point as mentioned.


  1. I like the thought of giving my guppies an atmosphere that they were meant to live in so I am going to switch over to the brackish version. thanks for the info

  2. Is it harder to look after this type of fish tank set up and is it more expensive?

  3. I have been using this type of set up for awhile now and don’t find it any more expensive other than buying the salt which isn’t that expensive. I think this is a better environment for my guppies.

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