How Long Can You Keep Betta Fry Together?

Female betta fry can usually stay together until they mature if the conditions are suitable. Still, male betta fish need to be separated from other males when they are between 8 and 13 weeks old, a practice known as “jarring.” The males will show greater aggression if kept together, especially if they are older, which is why separation is necessary.

In the following sections, we’re going to learn how to take care of multiple bettas, when they can be together, and when they need to be separate.

Can You Keep Betta Fry Together?

When they are young, keeping your betta fry together is not a problem. In fact, it is unavoidable at first since each spawning will include anywhere from 30 to 500 bettas!

The betta fry will not cause any problems for each other while they are juveniles, and by the fifth day, you will have already removed both of the parents from the tank, so the fry will not be interacting with other bettas during this stage either.

The important thing to remember is to approach the matter of your bettas’ cohabitation situationally. Because the distinction between males and females with regard to aggression isn’t absolute, and the timeframes of development are blurry, you need to be keeping an eye on your bettas so that you can take action when it’s appropriate.

How Long Can I Keep My Betta Fry Together?

Your betta fry can stay together until they begin fighting. Male betta fry will begin showing aggression when they reach the stage of development that coincides with their colors becoming more vivid and their fins becoming longer, which usually starts when they’re between 8 and 9 weeks old. Once they reach this stage, they become extremely territorial and truly live up to their common name of Siamese fighting fish.

The females will usually have no problem living together as fry, but contrary to the popular myth, they will also need to eventually be separated for their own well-being. If your female bettas do begin fighting as fry, however, you will need to separate these aggressive females as well since they’re capable of doing as much serious damage as the males are.

Where to Keep The Betta Fry Together

People use different arrangements for housing their betta fry. Some breeders will keep them in the tank that was used for breeding for the first few weeks and then move them into a separate grow-out tank, whereas other breeders may move them into the grow-out tank at the very beginning.

Whichever approach you take concerning housing, you should make sure that the aquarium your betta fry is in is suitable for them to survive and thrive in.

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20 Gallon Tanks

It’s true that tanks measuring 1 gallon or even smaller are common for housing bettas, but this is not advisable and will make for a very poor environment for them. By the time your bettas are in the grow-out tank, which should be no later than 6 weeks in, this should be at least 20 gallons in capacity.

Live Plants

This isn’t mandatory, but it will make for a much better environment for your fry. Plants like Java moss will mimic the bettas’ native setting while also improving the water quality in the tank. As an added bonus, live plants can provide the opportunity for infusoria to flourish, which your bettas can use as a nutritious food source.


The best water temperature for betta fry is in the mid-to-high 80s Fahrenheit. You will need an Tank Cover

You might be surprised to learn that betta fry can jump out of their tanks, and they will if you don’t make it impossible for them. Whether you use a professionally-made lid to go with your store-bought tank or something you’ve crafted at home for the same purpose, make sure that your fry can’t get out, nothing hazardous can fall in, and that there are air holes.


The plants won’t be able to do all the work. You’ll need an aquarium filter to keep your water clean, but more importantly, to keep it oxygenated. It’s easy to forget that fish need oxygen too, but they will die without it, so this is absolutely essential.


Sunlight is usually enough for your bettas, but it must not be too bright, so avoid placing your tank anywhere where there’s too much direct sunlight. On the flip side, if the tank doesn’t get enough light, this will negatively affect your betta fry’s growth. You can use an aquarium light as a substitute for mild sunlight in this instance.


Betta fries like having a place to hide. Live plants can cover this niche to an extent, but it’s good to give your bettas more structures to shelter behind. Common options are banana leaves and Indian almond leaves, which also improve the quality of the water in the tank.

(Find out how you can make your Betta fry grow faster here.)

When Should Baby Bettas Be Separated?

In extremely rare cases, male betta fry may begin coloring and showing aggression as young as 2-and-a-half to 3 weeks old. If this happens, regardless of how young they are, this is a signal for you to separate the aggressors into their own tanks.

While 8 to 9 weeks is the normal age for fighting among male betta fry to begin, if it does begin sooner, there is no reason to wait for them to reach the 2-month mark before separating them as they’ve already reached that stage in their development and aren’t going to regress to a stage where they’re able to live together again.

The same logic and need for early separation apply for female betta fry who begin fighting with their sisters at a very young age, although this scenario is even rarer, and you may potentially never encounter it.

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Although it can seem daunting and complex at first, we’ve seen how to take care of betta fry and when to separate them. Now you know that the 8-week mark is where male betta fry will begin to show aggression.

You’ve also learned the importance of spotting these aggressive acts regardless of the time frame and what physical changes the males will undergo when they reach this stage of development, from the bright colors to the longer fins.

Although often ignored, we’ve learned that female bettas can be aggressive as well, and separating these female aggressors is just as important as separating the male aggressors, even if they are less common.

We’ve also looked at how you can raise your betta fry in an appropriate environment that will ensure their health and growth and the two common practices of either moving them to a grow-out tank from birth or leaving them in the breeding tank for the first month.

Once the grow-out tank arrives, you know you need 20 gallons of capacity, heating to get the water in the mid-to-high 80s, a breathable cover to prevent your fry from jumping out, a filter to keep the tank oxygenated and clean, either mild sunlight or a suitable aquarium light leaves to shelter under, and some live plants for good measure, so you can raise happy healthy bettas.