How Long Should You Wait To Put Betta Fish In A New Tank?

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Getting a betta fish is always exciting. You may want to put your betta fish in the tank immediately. Unfortunately, this isn’t a great idea.

You should wait to put betta fish in a new tank until the tank has been cycled. Adding a betta fish to your tank is a slow process and there are a number of things that need to be taken into consideration first. Cycling your tank can take 4-6 weeks and is very important to ensure the survival of your pet! So, technically you will wait 4 – 6 weeks before you put betta fish in a new tank.

We will discuss cycling your aquarium in this article.

Betta Fish

Foremost, the newly installed tank should be up and running for a few days to make sure that all the equipment is working correctly, and the tank is free from leaks.

After checking your system, these are the three key steps to take when adding new fish to the tank:

  • 1. Cycle the aquarium
  • 2. Test the water and ensure the aquarium has cycled
  • 3. Acclimatize the betta fish.

Each one of these steps is just as important as the last so make sure you follow them when adding betta fish to your tank.

How to Setup and Cycle A Tank

Unlike humans, fish breathe in the same water they go to the toilet in. Fish excrement breaks down and produces “ammonia.”

Ammonia, if left in the water can become toxic to fish and will even kill them if it reaches high levels of concentration.

To prevent ammonia build up the aquarium needs a nitrogen cycle. The cycle takes care of harmful bacteria such as ammonia, nitrite, and nitrate.

Cycling is the process of the good bacteria colonies within the tank processing the toxic waste and turning it into non-toxic waste. Kick-starting the nitrogen cycle can take a long time. In total, this could take up to six weeks to fully complete.

The easiest way to understand cycling is that you feed your fish, the fish ingests its food, and then produces waste matter. All of the decomposed waste turns into ammonia which can be toxic to the fish.

Then the good bacteria, in your gravel bed and filter, will consume the ammonia and nitrates and convert them into nitrates. Nitrates aren’t bad for your fish at low levels but can cause issues at higher levels.

Regular water changes will keep your nitrate levels low.

How to Cycle the Aquarium

To start cycling you need to have your aquarium set up, this includes making sure there is gravel in the tank, the aquarium is filled with water, and that the filter is switched on. The good bacteria will already be present within the water!

There are a number of kits that can help kick-start your cycling process and we highly recommend using them. It ultimately simplifies the process and is more humane than cycling your aquarium with fish.

You can add plants to your aquarium at this stage, they are relatively unaffected by short-term water parameters and can aid in the cycling process.

While your colony of good bacteria grows you need to be patient and wait before adding new fish into the tank. In the meantime, continue to test the water and monitor the ammonia and nitrate levels.

You will notice a large spike in nitrite followed by a gradual increase in nitrates. This is usually a good indicator the cycle has almost completed.

While you wait, do your research into the fish you want to purchase for your tank. Be sure to select fish that are an appropriate size (fully grown) and will be compatible with each other (and water quality).

It is important that you do not add your new fish into the tank until the tank is ready.

How To Properly Transfer Your Betta Fish Into The Cycled Tank

Testing Water

Generally, when you have a rise and fall in nitrites, followed by a rise in nitrates this is usually a good indicator the cycle has completed (however this can sometimes deviate).

A testing kit can be purchased at all good pet shops, these include testing strips and an information key to help show you understand the results. Your cycling process will be complete when the ammonia and nitrite levels are at zero.

tetra easy strips PetAquariums How Long Should You Wait To Put Betta Fish In A New Tank?

The ammonia and nitrite concentration levels should stay at 0 and the nitrate should stay below 40 ppm. Nitrate levels are the key inside the testing kit to help you understand the results better.

Keep testing the water for a few days and if they continue to stay roughly the same results then you know that the cycle has worked, and you can start adding new fish to your tank.

Once your fish settles into their new tank the good bacteria will continue to grow and deal with the toxins. You can help this process by removing and changing 25% of the water each week.

This will help to keep the tank and the water clean and stop your fish from ingesting harmful toxins.

Acclimatizing the Fish

Unfortunately, it is very common for fish to die shortly after being added into a new tank. This could be because the fish itself was unwell when purchased, but it could also be because the new owner did not correctly acclimatize their new fish to the tank.

Adding new fish to your tank can be tricky. A lot of people place the fish in its bag in the new tank, leave it for a few hours and then add it to the water. This isn’t a good way to acclimatize your fish.

Steps to Acclimatizing the Fish

  • Turn down the tank lights: When you bring your new fish home, turn down the lights in the tank to avoid damage or shock to the fish’s eyes.
  • Place bag in the tank with edges rolled down: When adding new fish to the tank you should keep the fish in the plastic bag but roll the edges down and place it in the tank water to float. This way it will float steadily on top of the water and some of the water that is already in the tank will splash over into the bag.
  • pH levels: The next thing to consider is the pH levels, even a small difference such as 0.5 in the pH level could be fatal to the fish. If the pH levels are close or within two-tenths then they will equalize very fast, if they aren’t as close it will take longer.
  • Patience: When adding new fish to the tank, wait, the water’s pH levels being equal will give your fish the best chance at survival.

Acclimatizing is a slow process, you should gradually add cups of water from the tank to the bag during the first two hours of the bag floating in the tank. This will help the pH levels to slowly change so it isn’t such a shock to the fish’s body all at once.

Water Temperature

While you are waiting on the pH levels to equalize you can focus on the water temperature.

Tropical fish flourish best in waters that are between 76° and 80°F, it’s very important to keep these temperatures so make sure your tank has a precise thermometer.

Remember that all species of fish have slightly different needs so check with the specific species as to what temperature they require before you place them into the tank.


It’s very important to get your water and tank ready before adding new fish. This could be the difference between a healthy, content fish and a sickly fish or even worse, death. The last thing you want is for your new pet to suddenly get sick, especially when it’s something that you could prevent yourself.

Remember to take the correct steps to cycle and test your water, and to take the time to correctly acclimatize your fish.

If you follow these steps, adding new fish to your tank will be the easiest thing in the world.

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Pet Aquariums

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