Betta Fish Eggs: Be An Expert In Identifying Their Species!

Betta Fish Eggs
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Last Updated: July 13, 2022 by Flora Gibbins

One of the most fun aspects of breeding Betta fish is witnessing healthy fry (the hatchlings) emerge from the fertilized eggs in a bubble nest. 


When breeding Bettas, you’ll need to be armed with knowledge if you want a high success rate.

This article explains all there’s to know about Betta fish eggs, from what they look like and how long they take to hatch to the hatching process itself. Keep reading to learn about what to do when spawning these tropical fish.

What Betta Fish Eggs Look Like

What Betta Fish Eggs Look Like

Generally, Betta fish eggs look like small, white balls roughly 1 mm in size.

Not all the eggs appear fully round, so you might see a couple that looks like ovals. Moreover, egg sizes vary among different Betta species.

For example, mouthbrooding Betta fish lay bigger eggs between 2 and 3 mm.

You’ll know the breeding process has begun once you see a bubble nest on the water surface. Bubble nests look like a cluster of tiny bubbles. Soon, these bubbles will house fertilized eggs from which Betta fry will emerge. However, with mouthbrooders, it isn’t as obvious to tell because you won’t see a bubble nest (for reasons explained below).

How Many Eggs Betta Fish Lay

How Many Eggs Betta Fish Lay

Betta fish lay between 30 and 100 eggs per batch. However, some female Bettas lay 500 eggs in one sitting. As always, these estimates depend on the species of Betta that’s being spawned. For example, mouthbrooder Bettas can only manage to lay between 10 and 20 eggs per batch (you’ll find out the reason why below).

Additionally, the following factors determine how many eggs a female Betta fish is capable of laying:

Size and Age

The ideal time to spawn Bettas is when they’re six to eight months old. Although Betta fish reach sexual maturity around two to three months old, it’s always best to hold off on breeding them at such a young age until the females are the same size as the male fish. That’s because full-grown females are more likely to produce healthy eggs.

Smaller female Bettas lack the strength and capacity to make more eggs. In addition, some fish keepers have observed that the females are most productive at one year old, whereas you can expect your female fish to become less fertile around 2-3 years of age.


Female Betta fish that have spawned before are more likely to lay eggs. Additionally, when both male and female fish have spawning experience, there’s a greater chance of the male fertilizing the eggs and a higher hatch rate.

Moreover, if the Bettas have no experience, a lot of unfertilized eggs can be produced. In that case, you can expect the male to eat the eggs.


When you condition male and female Betta fish, it raises the success rate when the female lays eggs. Therefore, it isn’t advisable to attempt to spawn Betta without first conditioning them.

To condition your Betta fish, you’ll need to feed them high-protein frozen foods multiple times during the day. Also, showing the fish off to each other encourages breeding and egg production.

How Long It Takes for Betta Fish Eggs to Hatch

How Long It Takes for Betta Fish Eggs to Hatch

Usually, Betta fish eggs hatch within 2-3 days. However, some Betta eggs may take a mere 24 hours to hatch, while the eggs of other species of Betta fish-like mouth brooders typically hatch slower, taking up to a month. Many factors determine how quickly Betta fish eggs hatch. 

Some of these include:

Water Quality

Poor water quality hurts the Betta fish egg hatch rate. Eggs and fry are more likely to die when hatched in water with high ammonia levels. When there are plenty of harmful substances in the water, fish waste products, and bacteria, the ammonia levels will rise. Moreover, a dirty tank will prove harmful to your fish and the eggs they lay.

You won’t find Betta fish eggs lying on the tank bottom on an average day. However, the exception to that rule is when the eggs have hollowed out and died due to filthy tank conditions.

Additionally, poor water quality can cause stress in Bettas, which may make them exhibit erratic behavior. For example, the males may eat the fertile eggs and become too sick to care about breeding. Worst case scenario, they might die.

You’ll need to carry out frequent aquarium maintenance and water changes to prevent an untenable environment from ruining your spawning success rate.

Water Temperature

In waters with higher temperatures, Betta fish tend to have a higher metabolism and digestion rate, two characteristics that play a role in how quickly egg hatching occurs.

For example, eggs will hatch within 24 hours in water with a temperature of 75 degrees Fahrenheit, while in colder temperatures, you’re looking at an additional 48 hours before you witness any hatchlings.

You can try between 79 and 82 degrees Fahrenheit for optimum water temperature that promotes quicker hatching.

Betta Species

The species of Betta fish in your tank also determines how long it’ll take before you see Betta fry in the water. Bubble-nested Betta fish eggs hatch much more quickly than the eggs of mouthbrooding species, which take an average of one month to hatch. Moreover, Betta macrostoma eggs take even longer to hatch, more than one month.

Breeding Behavior to Watch

Breeding Behavior to Watch

You’ll be able to tell when a female Betta is willing to mate by observing its skin. First, its skin color darkens, and a barring pattern forms on it. Second, you should see a vertical stripe around its mid-section, indicating fertility. Third, when you observe that its egg hole opens more frequently, it’s a good sign it’s ready.

Meanwhile, male Bettas build bubble nests to create a safe space for the fish eggs. Betta fry can’t survive outside of bubble nests, so when spawning begins, the male Betta places the eggs in the nest after fertilizing them.

Eggs are fertilized as soon as they emerge from the egg hole of the female fish. 

Gray spots offer the most unambiguous indication that Betta fish eggs are fertilized. 

Additionally, when the eggs are on the precipice of hatching, you’ll be able to see a small fish inside surrounded by a white yolk sack.

Conversely, unfertilized eggs are easy to spot among the fertilized ones. They don’t have any gray spots on them, are white, and remain small even as other fertile eggs grow around them. After a few days, they become fuzzy, and you won’t be able to see the small fry within them.

Male Betta fish are responsible for caring for the fry. 

When the fry emerges from their yolk sacs, they can’t swim. While in this vulnerable state, they look to their father for everything, from protection to sustenance.

Moreover, you’ll need to keep an eye on your male fish. Usually, they eat infertile eggs to make it easier to provide care for the most fertile fry. However, they might eat the fertilized eggs when stressed or inexperienced. You’ll need to keep your male Betta in a stress-free environment before breeding to prevent this behavior.

A Little More About Mouthbrooders

A Little More About Mouthbrooders

So far, we’ve spoken about the Betta fish spawning process in the context of Betta splendens. However, the process is entirely different for mouthbrooding Betta fish (macrostoma and channoides). Unlike Splendens, mouthbrooders don’t create bubble nests. Instead, they hatch Betta fry inside their mouths.

The reason behind their behavior is their natural habitat. While other fish in the Betta species live in shallow pools with lots of oxygen, perfect for building bubble nests, mouthbrooding Bettas live in habitats with more currents.

The volatility of currents makes for tricky waters when making bubble nests. Therefore, mouthbrooders carry their fry in their mouths out of necessity.

In addition, mouthbrooders enjoy many benefits when hatching eggs in their mouth. First, they’re better able to guard their unborn offspring. Second, they can provide ample oxygen to the fry through their gills and mouth for better development. Third, they’re not restricted in movement the way bubble nesters, who can never leave their nests, are.

Of course, there are disadvantages to mouthbrooding. For one thing, mouthbrooding Bettas can’t eat while storing eggs in their mouths. For another, they’re sitting ducks for predators since the eggs can prove burdensome when the fish is placed in a confrontational situation. Finally, they can only carry so many eggs.

Fun Fact: Are betta eggs similar to goldfish eggs? Let’s prove (or disprove) this query by reading our article about the latter — Goldfish Eggs: Beginners’ Guide To Proper Care & Supervision.

Some Considerations to Keep In Mind

When breeding Betta fish, you’ll want to keep the following considerations in mind:

Separate Tanks

Separate Tanks

Initially, it’d be best to keep the male and female Bettas in separate tanks and only let them share the same one when you’re ready to breed them.

Male Behavior

Male Behavior

If the male Betta behaves aggressively toward the female, remove it from the tank. Such behavior indicates that the conditions aren’t suitable for spawning.

Fun Fact: Complete your betta fry education by proceeding to read our article regarding Baby Betta Fish: Comprehensive Guide To Proper Care for a more in-depth discussion on this subject.

Watch This!

Frequently Asked Questions

How often do Betta fish lay eggs?

Under normal circumstances, female Betta will lay eggs every few weeks. However, when a Betta fish is stressed, you can expect its spawning frequency to drop significantly. Moreover, if you have a weak male Betta that lacks experience producing and handling fertilized eggs, your chances of seeing an aquarium filled with tiny fry reduce even more.

Is it possible for Betta fish to lay eggs without a partner?

Female Betta fish can produce eggs by themselves. However, these unfertilized eggs won’t hatch and will most likely rot. Rotting eggs that don’t hatch into Betta fry will likely raise ammonia levels in the water, so you’ll need to watch for them.

What should I do after my Betta fish lay eggs?

Once female Bettas lay their eggs, remove them from the tank. Their job is done, and the task of caring for the unborn fry until the Betta eggs hatch falls to the male Betta fish. However, if you find that the male is eating the eggs, remove it from the tank as well.


So, there you have it. We’ve explained everything you need to know about Betta fish eggs. You should now be able to tell when spawning is about to begin, what bubble nests look like, and the difference between a fertilized and unfertilized egg.

Remember, mouthbrooder Betta fish are best for fish keepers who don’t want more eggs than they know what to do with, so stick with this species if that sounds like you. Also, keep in mind that tank water quality and temperature may affect unfertilized eggs. In addition, always watch the male Bettas’ behavior as they’re responsible for the eggs.

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