How Long Should You Wait to Put Betta Fish in a New Tank?

Bettas have a reputation of being tough, hardy fish that can live through anything. In the wild, they can survive in shallow puddles during the dry season. In the pet store, they live in small cups. Surely they’d be better off if you brought them home and put them in a new tank, right?

Not exactly. Although a five or ten-gallon aquarium is a much better home than a small plastic cup, it’s not quite that simple. Just like any other fish, you shouldn’t put a betta into a new tank right away. In fact, it can take weeks before your new tank is ready for your betta.

The first step? Cycling your tank.

Cycling the Tank

Bettas and all other fish breathe through the water in their aquarium, but this water also contains fish waste, uneaten food, algae, and other kinds of detritus. When these things break down in the water, they produce ammonia, which is toxic to fish.

A properly cycled tank is necessary for taking care of ammonia. A cycled tank is one that has enough good bacteria in it to take care of the ammonia, essentially turning the things that are toxic for your betta into things that are not.

Good bacteria grow in both the substrate and in the aquarium filter. These bacteria colonies ingest the ammonia and convert it into nitrites and then break it down further into nitrates. Nitrates aren’t as toxic for your fish, and they are normally taken care of with regular water changes.

Before you can add a betta to your tank, you have to make sure that the tank is properly cycled. To do so, put gravel in the bottom of the tank to give the bacteria plenty of places to grow. Set up a filter, and let it run.

Testing the Water

To make sure the tank is cycled properly, you have to test the water. You will commonly see an early spike in ammonia, then as the bacteria colonies get established, the ammonia will fall, and the nitrites will rise.

As your tank gets established, you will eventually see no ammonia, a small amount of nitrites, and some nitrates. When there is no ammonia and you have seen the nitrites spike and fall, it’s a good sign that the cycle is complete.

The only way you can know for sure is to test the water with a testing kit. When you consistently test and see no ammonia, no nitrites, and nitrates below 40 ppm, your tank is ready.

When you add your betta, you may see a small spike in ammonia or nitrites, but the bacteria should continue to grow and adjust to the new bioload. Keep checking the water and do a 35 percent water change every week.

Acclimating the Fish

Once your tank is cycled, it’s time to go get your betta. But you’re not quite ready to add it to the tank just yet. Many fish die because they are added to the tank too quickly, without having a chance to acclimate.

The point of acclimating a betta or any fish to a new tank is to make sure that the change from the water they in when you get them from the pet store isn’t too different from the water in your aquarium. Specifically, you want to be careful that the pH and the temperature are not too much different.

So, how do you acclimate a betta fish to a new tank? Slowly.

Many people keep the fish in the bag it came in and let it float in the water for a few hours. This technique has the right idea, but there are a few other steps to add.

First, instead of just floating the bag on the surface of the tank, open the bag and roll the sides down a little first. This way, the bag will float on the surface and some of the tank water will splash into the bag.

Slowly add a cup of water from the tank into the bag and allow the bag to float for two hours. Mixing the water like this gradually changes the pH level that the fish is living in so as not to shock it all at once.

The same is true about the temperature. Your tank will likely be a little warmer than the water that the betta was living in in the pet store since they are usually kept in small cups that do not have heaters. By allowing the fish to slowly acclimate to the new warmer temperatures, you avoid shocking it.

(If your betta came in a plastic cup, you can ask the pet store for a plastic bag and transfer it into the bag to float it on the water. Or, you can add water from the tank directly into the plastic cup).

Final Thoughts

How long should you wait to put a betta fish in a new tank? Unfortunately, there’s no straightforward answer to that question. The most important thing is that you wait for the tank to cycle, which can take anywhere from four to eight weeks.

Though this might seem like a long time, in the end, it’s worth it. If you add your betta to the tank before it’s cycled properly, there’s a good chance that the water will stress the fish, and your new pet might not make it.

Once you have tested the water and know that the tank is properly cycled, it’s time to go get your betta. When you get your new pet home, don’t just immediately drop it into the tank. Take the time to acclimate it over a few hours to avoid shocking its system.

Preparing the water and taking the time to acclimate your betta are two of the best things you can do to start your new aquarium off right. Getting the water just right and giving your fish time to get used to it ensures that your new pet is happy and healthy.