How to Acclimate Freshwater Fish

To acclimate freshwater fish it is important to prepare the tank beforehand to give the fish the best chance of survival. Freshwater fish can range in size from one inch to 13 inches. It is important to have a tank the correct size for the fish that will inhabit it. A 10- to 20-gallon tank is only suitable for small fish. The tank should be placed out of direct sunlight and drafty areas. Fish can become stressed when they are moved to a new environment. This can lead to illness, so it is important to introduce them correctly.

Things You'll Need

  • Tank
  • Heater
  • Nitrogen cycling additive
  • Chemical test kit
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Instructions

    • 1

      Prepare the water in the aquarium by placing a heater on the inside of the tank. Leave it for 24 hours to allow the water temperature to stabilize. Add a few drops of nitrogen cycling additive and wait another 24 hours. Test for ammonia and nitrate in the water using a kit with chemical test strips and a key to assess the results. Test kits are available to purchase online and at pet stores that specialize in fish keeping. Once the levels of ammonia and nitrate are non-existent, the water is ready for the freshwater fish to be introduced.

    • 2

      Add fish one or two at a time by placing the bag that is currently holding the fish into the tank. Keep the fish in the bag and leave for 15 minutes to allow the fish to acclimate to the temperature of the water. Add some of the tank water to the bag and leave for five minutes. This will allow the fish to become acclimatised to the pH level of the water in the tank. Allow the fish to swim from the bag out into the tank. It is best to introduce hardy fish to begin with, such as cherry barb and zebra danio as this will help to prepare the water for the rest of the fish.

    • 3

      Leave a day before feeding the first new fish as they will be too stressed to eat until they have settled into their new home. Always feed the fish 24 hours before adding more fish to reduce aggressive behavior from the original fish toward the newcomers. Ensure there are a number of hiding places in the tank by providing objects such as rocks and plants. This will help to greatly reduce the stress of new fish joining the tank.