Guides > Adding new fish to your tank
Transport the fish in a plastic bag from the store. Most pet stores put fish in a clear plastic bag filled with water. Make sure you keep the fish in a dark place as you transport him home from the store.

Try to get him home right away as he will need to be introduced to the tank soon after being placed in the plastic bag. This will reduce his levels of stress and help him acclimate faster to the tank water. Your fish may lose some of his coloring during the trip home but don’t worry, this is normal and your fish should recover his coloring once he is in his tank.

Turn off the lights in the aquarium. Dim or turn off any lights in the aquarium before you add your new fish, as this will create a less stressful environment for the fish. You should also make sure your tank has plenty of plants and rocks as hiding places for your new fish. These will help him feel less stressed out as he gets used to his new home.

Add more than one fish at a time. Adding more than one fish at a time will ensure your existing fish can get used to the new additions. It also prevents one fish from getting harassed by the other fish, as the existing fish will have multiple new friends to bond with. Introduce new fish in small batches of 2-4 so you do not overwhelm the tank.

Always choose fish from the store that appear healthy and disease free. You should also carefully monitor your new arrival for the first several weeks to ensure there are no signs of disease or stress.
Some aquarium owners will place their new fish in quarantine for two weeks to ensure he does not have any diseases or infections. If you have the luxury of time and access to another clean tank you can use as your quarantine tank, you can try this option. If you notice the fish gets sick in the quarantine tank, you can treat him without affecting the other fish or the chemistry of the new tank.

Place the unopened plastic bag in the tank for 15-20 minutes. Let the unopened plastic bag with the fish float on the surface of the aquarium. This will give the fish time to get used to the temperature of the tank water.

After 15-20 minutes, open the bag and use a clean cup to scoop an equal amount of water from the tank into the plastic bag. There should be twice as much water in the bag, 50% tank water and 50% pet store water. Make sure you do not mix the water from the bag into the tank water as this could contaminate the tank water.

Allow the bag to float in the tank for another 15-20 minutes. You can seal the edge of the bag to keep in from spilling out.

Net the fish out of the bag and place him in the tank. After 15-20 minutes, release the fish into the tank. Do this by netting the fish in the bag and gently placing them into the water of the aquarium.

You should monitor the fish for any signs of disease or illness. If there are already other fish in the tank, you should make sure they are not harassing or bothering the new addition. With time and proper maintenance of the tank, all the fish should co-exist happily.