How to Set Up a Brackish Water Aquarium

Most new hobbyists know that they can choose to set up either a freshwater or a saltwater tank, but there is a third option they might not be aware of. Many fish live in bodies of water where freshwater streams and marshes meet the open ocean. The water they inhabit is less salty than seawater but not completely freshwater as well. These brackish water fish include some of the most beautiful and fascinating in the aquarium hobby, including gars, scats, puffer fish and mollies. Setting up a brackish water tank is a wonderful way to bring the beauty of nature into your home.

Things You'll Need

  • Aquarium
  • Sand or gravel
  • Driftwood
  • Rocks
  • Plants
  • Filter
  • Plastic bowl
  • Water
  • Aquarium salt
  • Hydrometer
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Instructions

    • 1

      Choose a suitably sized tank for the fish you plan to keep. A good rule of thumb for brackish tanks is to keep no more than 1 inch of fish per gallon of water, so four 3-inch mollies and a 5-inch puffer fish should do fine in a 20-gallon aquarium.

    • 2

      Lay down a good layer of aquarium sand, play sand or fine gravel in the bottom of the tank. Play sand is a good alternative to the costly sand sold in pet stores, and the fact that it is sterilized makes it safe for aquarium use. Use at least 2 to 3 inches of sand or gravel in the tank.

    • 3

      Choose natural decorations that you might find in a brackish body of water. Driftwood, small plants and rocks are all good choices. Arrange the decorations to create a natural look for your tank.

    • 4

      Buy a power filter and put it in place on the back of the tank. Choosing a power filter designed for a larger tank than you actually have will give you the extra filtration power you need.

    • 5

      Place a large, deep bowl in the middle of the aquarium, then slowly fill the tank with fresh water. If you have town water, be sure the water has been declorinated, or use spring water instead. Fill the tank slowly to avoid uprooting your plants and disturbing your decorations.

    • 6

      Add 2 tbsp. of aquarium salt per gallon of water to start your tank. Use only salt designed for aquariums, never table salt or rock salt. Aquarium salt contains not only salt but a carefully developed balance of minerals needed to keep both saltwater and brackish fish healthy.

    • 7

      Perform your monthly water changes just as you would with any tank. Changing one-third of the water every month is the best way to keep the water quality high and the fish healthy. Add 2 more tbsp. per gallon of water every time you change the water. Continue doing this until the hydrometer in your tank has a reading of 1.020 to 1.025.