How Long Can Betta Fry Live Together?

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Adult betta fish can be pretty aggressive, especially the male ones. That immediately raises the question regarding their offspring. In this article, I will discuss how long betta fry can live together in the same tank and when is the right moment to move them.

On average, betta fry can live together for eight weeks. After that, it is better to move them out of the tank into separate ones. Betta fry can live longer together if they have enough hiding places, room for swimming, and when most of them are females.

As we move forward, I will show you in which cases you should move your betta fry sooner than eight weeks. Then, I’ll discuss the right way to transfer them and what precautions you should take.

Five weeks old female betta fish fry.

Still curious? Feel free to check my complete guide on betta fish fry, where I discussed how to care for betta fry, what they eat, their growth stages, what equipment to use, and much more.

How Long Can Betta Fry Live Together?

Unfortunately, this question doesn’t have a definitive answer. The average aquarist will encourage you to keep the following factors in mind:

1. The Type Of Your Tank

Did your betta fry hatch in the spawning tank or grow-out tank? Some aquarists will keep their baby bettas in the spawning tank for the first few weeks before moving them to the grow-out tank. 

But others prefer to start with the grow-out tank. They will add the breeding pair to a tank large enough to accommodate mature fry. 

Spawning tanks are problematic because they are typically too small to house the babies in the long term, especially if they are tall and narrow.

Therefore, you have to move them before the size limitations compromise their health. If the betta fry hatched in a grow-out tank, you have more room to breathe. The fry can stay in the aquarium until they are large enough to survive in the community tank.

2. The Betta Fry’s Temperament

In most cases, temperament isn’t an issue. Young bettas can coexist peacefully with one another. However, anyone that has ever raised fish will tell you that the creatures have unpredictable personalities.

Don’t hesitate to separate the baby bettas when you observe aggressive behavior among them. Sometimes, it is enough to move the fish to a larger tank. 

Like their adult counterparts, small and crowded conditions can induce stress in baby bettas, encouraging aggressive tendencies.

In other words, you can diffuse the aggression by simply giving the fry a spacious aquarium. If the tank is large enough, but the babies are still fighting, separate them.

A couple of days old betta fish fry, still hanging to their bubble nest.

3. Males vs. Female Betta Fry

Gender is the most crucial consideration. People don’t expect fish fry to antagonize one another, as they know that fish offspring can coexist peacefully.

But betta fry are unique because adult males cannot live in the same tank. You should only keep one male betta per aquarium.[1] Otherwise, they will fight incessantly.

You don’t have to concern yourself with newly hatched males because they tend to behave. But as they mature, their territorial tendencies will present a challenge. 

This is why many aquarists prefer to separate the male bettas before their hostility destroys the tank’s balance. This is not an excuse to keep the males in isolation. 

An article in BMC Zoology found that male bettas raised in a group were less aggressive than male bettas that aquarists reared in isolation.[2]

You can surround a male betta with female bettas. Unlike male bettas, multiple females can live peacefully side by side. Of course, you can’t keep male bettas away from each other if you don’t know what they look like. 

Male bettas have distinct attributes that separate them from the females, including:

  • Male bettas have long, flowing fins. The females always stand out because their short fins are not as impressive. 
  • Male bettas are more colorful. The females are pretty dull in comparison. 
  • The females have an ovipositor, a white dot near the ventral fin. The eggs emerge from the ovipositor.[3]
This image shows the ovipositor, seen in an adult female betta fish.

When Should I Move My Betta Fry Out Of The Tank?

You can move the betta fry after eight weeks.[4] As I previously discussed in my betta fry growth stages guide, at two months of age, the fry are considered young and can reach a size of 1.4 inches.

You will notice the male betta’s aggressive mannerisms at this stage. Additionally, the gender is so much easier to identify because the bettas have already developed distinct features at eight weeks.

You can see the male betta’s flowing fins and vivid colors. You can also see the ovipositor on the female. You have no reason to keep the fry together beyond this stage.

Although, some aquarists prefer to wait 13 weeks before moving the fry out of the tank. Their primary consideration is their tank’s size. 

For instance, aquarists with larger aquatic environments like ponds can keep their fry together for four months.[5]

On the other hand, homeowners with smaller spawning aquariums can move their fry in as little as four weeks.[6]

I also suggest keeping the number of fry in mind. An aquarist with 500 baby bettas won’t wait as long as a homeowner with just 20 or even 30 betta fry. A large population of baby bettas will create crowded conditions in a shorter period. 

How To Move Baby Bettas To A New Tank

Some people use cups. They scoop the babies out of the spawning tank and pour them into the grow-out tank. But this process is tedious, especially for aquarists with hundreds of fry.

Others prefer nets, air tubes, and turkey basters. But if you have a conventional spawning tank, the small kind that most homeowners use, you can transfer all the fry at once:[7]

  • Remove inconvenient hardware like heaters and filters. You don’t have to remove these devices if their presence doesn’t interfere with your work.
  • Carry the container with the baby bettas to the new tank.
  • Place the container on the surface of the tank. Let it float in the water. The goal is to acclimate the babies in the container to the temperature in the new tank.
  • Wait one or two hours. Transfer the fry to the new tank by pouring the water in the container into the grow-out tank.

What Precautions Should I Take During The Transfer?

You have to take certain precautions to protect the fry from stress and shock. Otherwise, they will die:

  • The new aquarium should be larger than the spawning tank. Aim for a minimum of 20 gallons.
  • Make sure the new tank is cycled correctly. If it is entirely new, you should introduce products with nitrifying bacteria, such as the API QUICK START (link to Amazon).
  • You should condition the new tank. Keep the chlorine and ammonia levels at zero. Baby bettas cannot survive in a toxic environment.
  • The parameters of the new aquarium should match the parameters of the spawning tank. Test the temperature and pH.

A mismatch in parameters can induce shock in adult bettas. That shock can kill your entire batch of betta fry.

To measure the pH, ammonia, nitrates, ad nitrties, I personally use the well-known API Master Test Kit (link to Amazon). It is highly accurate and lasts for hundreds of measures.

The new tank’s water parameters must match the previous one. It’s even more important than the actual numbers, even if they are out of range.

  • If the new aquarium has adult fish, feed them. Starved fish will attack new additions to the aquarium, especially if those new additions are small, delicate, helpless betta fry.[8]
  • If the new aquarium has aggressive bettas and their territorial behavior concerns you, take the bettas out and rearrange the plants and decorations before adding the adult bettas and their offspring.

It would help if you kept young and adult bettas in separate environments. But if you don’t have any spare tanks, adult bettas and fry can share a tank if you add hiding spots like plants and decorations.

Rearranging those plants and decorations can alleviate the tension by destroying pre-existing territories. This tactic is helpful because bettas are highly territorial.

If all this process sounds intimidating, feel free to check this article, where I discussed what you should do with betta fry, step by step. When appropriately done, about 90 percent of the fry can survive.

Two months old female betta fry, living together peacefully.

If you found this article helpful, these may also interest you:

Pro tip: If your betta fish breed frequently, you probably need to know a little about their eggs. You can find my complete guide on that topic here.


Betta fry are not aggressive like their parents, which is why they can coexist in the same tank for a while. However, as they grow, they might threaten each other, especially the male ones.

For that reason, you should move them out of the tank after eight weeks. They are big enough to eat and harm one another at this point. 

The males should be taken out after eight weeks, but the female can live in the same tank longer than that. That is also true for a male fry surrounded by females.

When moving the grown fry to a new tank, the most important thing is to ensure the water parameters are the same as in the original one. You can even use the same water; it doesn’t really matter.