Introducing New Fish to the Tank

Someone must have told you: “Open the fish bag and leave it in the water for at least 15 minutes, and then you can release them into the aquarium!”. 

That is perhaps the most famous direction on how to introduce new fish to the tank a new environment. Although partially correct, this advice is incomplete.

So, how long do you have to wait to put fish in a new tank?

I want to guide you on how to introduce new fish, shrimp, snails, etc., into your tank safely for the newcomers and the current aquarium inhabitants.

The same process applies when you are introducing new fish to a new tank.

Precautions

Always check if the fish you want is compatible with your aquarium water (pH, Water Hardness, and water temperature – read more here).

Transportation

Try to go directly from the pet store to your house. Don’t let the fish bag in your car for a long time.

Quarantine

It is strongly recommended that you keep new fish, shrimp, and snails in a separate tank (quarantine tank) for 7 to 10 days. There are two main reasons why you should follow this recommendation:

• Fish, shrimps, and snails share the same water at the fish store with many other fish. Stores usually have 3 or 4 large water filters (one for each type of water) that keep filtering all tanks’ water. Fish that just arrived share the same water with old ones, and sometimes, you can have one or two sick ones spreading disease to all of them. Fish Stores do their best to quarantine their new fish and handle sick fish immediately, but occasionally, you can bring an ill fish home. If you follow the 15-minute rule and put your fresh fish together with the others without doing the 7 to 10 days quarantine process, chances are you will spread that same disease to all your old fish, snail, and shrimps. 

• Imagine the stress the fish go through from the moment they leave the fish farm until they arrive at your home. In my years of aquarism, I learned that keeping them in this quarantine tank, in the dark, with good water and temperature, being fed accordingly, etc. (like a five stars hotel) really helps them to survive and be happy in their new home.

Preparation

Prepare your quarantine tank days before.

Watch this Youtube video to learn more about “How to Make a Quick & Easy Quarantine Tank”

Compare the fish bag water pH with the water from your quarantine tank.

If there is a difference of more than 1 unit (pH 6 and pH 7, for example), do the next steps, taking double the time I am suggesting.

Acclimatization Quarantine tank

1. Turn off your quarantine tank light.
2. Open the fish bag, keep it open, and leave it floating in the quarantine water for at least 15 minutes. Allow the bag to float upright. Take care to avoid the bag not to sink into the quarantine tank.
3. After at least 15 minutes, add about 1/3 of a cup of water from your quarantine tank water into the bag.
4. After another 15 minutes, add another 1/3 of a cup of water again.
5. Again, after another 15 minutes, add another 1/3 of a cup of water. Turn off your quarantine tank light.
6. Open the fish bag, keep it open, and leave it floating in the quarantine water for at least 15 minutes. Allow the bag to float upright. Take care to avoid the bag not to sink into the quarantine tank.
7. After at least 15 minutes, add about 1/3 of a cup of water from your quarantine tank water into the bag.
8. After another 15 minutes, add another 1/3 of a cup of water again.
9. Again, after another 15 minutes, add another 1/3 of a cup of water.

Adding the Fish to the Quarantine tank

Net the fish out of the bag and add them to the quarantine tank. You don’t want to mix the Pet Store water with your water.

Keep your fish in quarantine for 7 to 10 days.

Please keep your eyes on them.

Look for white spots, weird behavior, and disease symptoms.

Acclimatization – Definitive tank

1. Use a clean plastic bag or zip-lock plastic bag and fill it with water from the quarantine tank.
2. Net the fish from the quarantine tank and add them to the bag.
3. Turn off your tank light.
4. Put the new bag in your aquarium and leave it floating in the water for at least 15 minutes. Allow the bag to float upright. Take care to avoid the bag not to sink into the tank.
5. After at least 15 minutes, add about 1/3 of a cup of water from your quarantine tank water into the bag.
6. After another 15 minutes, add another 1/3 of a cup of water again.
7. Again, after another 15 minutes, add another 1/3 of a cup of water.

Adding the Fish (Definitive tank)

Net the fish out of the bag and add them to the tank.

Note: I like to put them in the final tank at night as they will have more time to adapt and get comfortable with the new environment.

Why wait 24 hours to put fish in tank

The reason for this general advice comes exactly from the fact that new fish can bring diseases, as I explained before here.

When they are at the fish store, they share the same water with other fish, and they are usually stressed and with low immunity.

I want to reinforce that 24 hours is not enough to see signs of disease, and you must keep your fish in quarantine a little longer, as explained here.

Conclusion

How long do you have to wait to put fish in a new tank?

The acclimatization process is necessary for new fish, shrimp, or snails arriving from the store. Make sure to complete this step.

The same exactly process must be done when you are introducing new fish to a new tank but in this case, make sure your aquarium is cycled (read more here) and your pH and Ammonia levels are safe (learn more here.)

Don’t risk spreading disease to all your fish just because you want to get your new fish into your aquarium quickly. 

Take care of yourself and your little aquatic friends.