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How To Tell If Betta Eggs Are Fertilized? | 12 Unheard Facts |

Identifying fertilized betta eggs from unfertilized eggs is not a hard task. You only need the correct guidance and a keen eye. I can give you the correct guidance via this article and I am sure this article will help you to develop your keen eye.

How To Tell If Betta Eggs Are Fertilized

What Do Betta Eggs Look Like?

Betta fish eggs are relatively similar to the eggs of other fish. But if you clearly watch them, you can distinguish betta fish eggs. These eggs are small in size, usually around 1 mm. However, when we consider the shape of the eggs, they are not all fully rounded. Eggs are unequal oval shapes. 

But mouthbrooding betta eggs are bigger than normal betta eggs. This male mouthbrooding betta fish keeps their fertilized eggs in their mouth to protect them. They are doing this until the fry release. Also, mouthbrooders’ eggs take a long time to hatch. These eggs turn more yellow when they develop. 

What Color Are Fertilized Betta Eggs?

The fertilized betta eggs have grey spots in the eggs. Other than that, you can identify fertilized betta eggs by their appearance. If the fertilized eggs are slightly growing, it will be a good sign.  These are the two main noticeable factors to determine whether the eggs are fertilized or not. However, you cannot get fry just by spawning two betta fish. Because laying eggs is not enough to get betta fry. The eggs must be fertilized to generate fry.

How To Tell If Betta Eggs Are Fertilized

What do unfertilized Betta eggs look like?

If your betta eggs remain white after some days, it is not a good sign. Moreover, if they turn fuzzy, they are not appropriately fertilized. Also, in these eggs, you can not see gray spots. However, sometimes, you can see unfertilized eggs in your aquarium. This can happen due to several reasons. 

If female betta fish or male fish, or both, are not fertile, it will cause them to generate unfertilized eggs. Further, when your pair does not have enough experience, they will create unfertilized eggs. On the other hand, it is very rare to fertilize all the eggs in a spawn. Usually, you can find both fertile and infertile eggs in a spawn. But in some cases, all eggs are not fertilized. Mainly, this will happen as a result of infertile parents. 

What Happens To Unfertilized Betta Eggs?

Most probably, male betta fish tend to eat unfertilized eggs. They eat not only unfertilized eggs but also damaged eggs. Because male fish only care about the fertile fry. But in some cases, male betta fish tend to eat all normal eggs. This can happen as a result of stress. So, to avoid or decrease this, you can allow them to live without stress in your tank. Therefore, give enough rest to your male betta fish. Especially keep in mind to create a secure and better environment in the tank. 

How Many Days Does Betta Fish Eggs Take To Hatch?

Generally, it takes about 2-3 days to hatch betta fish eggs. However, this hatching period depends on different factors. But mouthbrooder betta eggs take much time to hatch. The average time is around 10-14 days to hatch their eggs. However, it may be longer, up to a month. In addition to that, the below-listed factors can decide the hatching period of your betta fish eggs. 


Normally betta eggs fully develop in the water. Thus, the water conditions directly affect the eggs. Also, water temperature is the main concern to hatch them. In higher temperatures, the metabolism rate is high. And also, digestion is faster in high temperatures. So, these factors directly impact egg hatching time. 

For instance, if you keep the eggs in 75oFahrenheits, eggs will hatch within a day. But the eggs are in an environment that has a colder temperature; they will take more than three days to hatch. Therefore, you should try to keep them in a preferred temperature range. 

Water quality 

Secondly, you should consider the water quality of the tank. It determines how fast betta eggs hatch. Thus, it will highly affect to hatch rate. As a result of poor water quality, you can lose some eggs or fry. But eventually, all eggs and fry can die in the worst condition. Here, you should highly consider the waste load of your betta tank because fish poop contributes to a large amount of waste. 

Also, these wastes can increase the ammonia level of the tank water. Ammonia is very harmful to your betta fish, including their eggs. In addition to ammonia, poor water condition includes many harmful substances and metals. Because of that, you should keep the tank water clean. If not, it will cause to damage the vulnerable betta eggs. 

Special note 

You can enhance your water quality by performing water changes before spawning. Also, you can keep water quality by putting some catappa leaves in the tank.

In addition to that, you can set up a sponge filter in your betta tank.  These methods help to reduce the risk of harmful chemicals. 


The hatching period also depends on the species that your betta fish belong to. Because there are different betta species, and each species has a different hatching period. For instance, it will take a small period to hatch bubble-nesting betta. But comparatively, mouthbrooding betta fish eggs take a long time to hatch. Additionally, another example is betta macrostoma. Eggs of this betta species take more than one month to hatch and free-swim. 

How Long Does It Take A Female Betta To Lay Eggs?

Generally, female betta fish mature when they reach the age of 2-3 months. So, from this age, they can lay eggs. But it is not recommended to breed small females at such a young age. Because the breeding process needs a lot of energy, also, it has a risk for a small betta fish life. 

Further, large and older female fish can lay more eggs than small ones. Because small females do not have the capacity to carry all the eggs. Also, they do not have enough energy. Because of that, it is better to wait until they reach their maximum size. Usually, the most productive age of female bettas is around one year.

However, their age becomes second to their size. Anyhow if your female reaches their maximum size but still is three months old, it is safe to breed. However, this theory similarly applies when your female fish is older but small. Generally, female betta fish take around six months to grow their maximum size. So,  eight months old bettas are ideal for spawning.

Because at this age, female betta became mature. So, this fish is strong enough to produce healthy eggs. Female betta fish are fertile their whole life. But when they reach the age of 2-3 years, they will start to gradually lose their fertility. Also, at this age and after this age, they will produce fewer eggs. 

Can Betta Eggs Hatch Without a Bubble Nest?

Yes. Betta fish eggs can hatch without a bubble nest. But in this case, their survival rate can be minimal. Because betta babies are difficult to survive under normal conditions without a bubble nest. So, even if this happens without a bubble nest, it is not much success. However, the above-mentioned impact is relevant to bubble nest bettas only. For instance, the below-listed betta fish can be named traditional bubble nest bettas. 

  • Bettasplendens or Siamese fighting fish
  • Bettasmaragdina or Emerald betta
  • Bettabellica or Slender bettas 
  • Bettaimbellis or Crescent betta 

Mouthbrooder Bettas

There is another type of betta breeder, namely mouthbrooder bettas. Anyhow this betta follows another technique to keep their eggs until they hatch. Similarly, they will incubate the eggs but do not keep eggs in a bubble nest. They keep the eggs in the mouth of male fish. However, if you watch these mouthbrooder bettas, they have bigger jaws and bigger mouths. Because of that, male fish can hold their eggs in the mouth for multiple weeks until the eggs hatch. These eggs have more vital benefits via this technique than bubble nests. 

  • The first one is, that the male betta’s mouth is a better secure environment for their babies. Also, it is an experience good cover. 
  • Secondly, eggs can collect enough oxygen via the gills and mouth. As a result of good oxygen flow, the egg and fry development is increased. 

On the other hand, there are several disadvantages too. These are:

  • Firstly, male mouthbrooder fish can not eat when they incubate the eggs. 
  • Comparatively, the mouth has more limited space than a bubble nest. Therefore, mouthbrooders can keep a small number of eggs. 
  • Additionally, these eggs take much time to hatch. 
  • Also, betta fish are vulnerable to predators. 

For instance, these are some mouthbrooder betta fish species. 

  • Bettapicta or Java mouth-brooding betta
  • Bettapugnax or Penang betta
  • Betta raja 

Can Betta Eggs Hatch On The Floor? / On Bottom Of Tank?

No. Usually, betta eggs do not hatch at the bottom of the tank. However, some people say that you can help eggs to hatch by lowering the water until they touch the tank bottom. But it is complex. 

Can Female Betta Fish Lay Eggs Without A Male? 

It is possible to lay eggs by female betta fish without a male betta. But these eggs do not hatch and release the fry. Because they are not fertilized without male fish, usually, these eggs tend to rot. Then these rotten eggs will lead to producing ammonia and nitrates. Normally, if your female fish are healthy, they are always carrying some eggs. Further, they will continually reabsorb and recreate the eggs. This process will happen if there is no male betta fish in the tank. 

Do Male Betta Fish Lay Eggs?

No. Male betta fish do not lay eggs. It is the responsibility of female betta fish. Similarly, male betta fish also have a responsibility for eggs. Also, male betta fish create a bubble nest. After laying the eggs female, male fish place them in a bubble nest and incubate their eggs till they hatch. Male fish is watching and protecting the eggs in this time period. Also, they will catch and replace the eggs that fall out. 

Betta Eggs Are Not Hatching, Why? 

In some cases, you can see some eggs do not hatch. This can happen due to several reasons. These are:

Unfertilized eggs

After spawning, it can be possible to have some unfertilized eggs. These unfertilized eggs do not hatch. The main reason to generate unfertilized eggs is infertile male bettas and/or infertile female bettas

Poor water quality 

Further, if your tank water has poor quality, it will cause your betta eggs before they hatch. Because of that, you should maintain preferable water parameters. Moreover, you should minimize or eliminate the ammonia, nitrate, or nitrite levels in tank water. 

Additionally, you can keep good quality water in your tank by some simple practices. For instance, you can perform water changes to keep quality in your water condition. In addition to that, you can put some catappa leaves into your tank to reduce the harmful chemicals. 

Poor temperature 

If your betta fish eggs do not have ideal temperatures, eggs do not hatch. In this case, eggs can take more time to hatch. Because temperature can directly affect the hatching period of the eggs. The ideal temperature is 75oF.

Eggs Do not attach to the bubble nest

A bubble nest provides a secure environment for your betta fish eggs. Anyhow, when eggs do not attach to the bubble nest, it isn’t easy to survive them. So, it will cause them to die before they hatch. 


Betta eggs are the key factor that generates offspring. Also, offspring can maintain the betta population. A bubble nest is a protective home for these eggs. This nest is the creation of male bettas fish. After spawning, you can see small eggs in the bubble nest. Also, female betta fish can lay over 400 eggs in a batch. So, it would be best if you prepare to take care of betta fry after a few days. 

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About Dr.Chamika

Hello, I'm Dr. Chamika. I am a Researcher in Water quality, Aquatic organisms, and Environmental chemistry. I am a passionate fish keeper, with10 years of experience. My mission is to help other aquarists experience the joy of fish keeping.