March 15

Sarah Robertson

How to Tell if Betta Eggs Are Fertilized

If you're breeding Bettas, one of the most important things to know is how to tell if the eggs are fertilized. If they're not fertilized, the eggs will not hatch, and so it's important to make sure that you're doing everything correctly!

Sometimes even experienced fish keepers are not sure whether the eggs they see on the glass pane or in an opaque spawning trap are fertilized or not. This is why we decided to write this short article about ‘how to tell if betta eggs are fertilized’. Unfertilized Betta eggs are tiny, oval-shaped white orbs in an aquarium. The male Betta is responsible for fertilization to spawning, but the laying of the eggs is carried out by the female Betta.

The fertilized eggs of fish grow in size each day and have a distinct gray spot in the middle, suggesting fertilization. It's also worth noting that the fry that will emerge from the fertilized eggs are frequently known as Fry. Unfertilized fish eggs, on the other hand, will be completely white and will grow fuzzy and not develop if you look at them for a few days. Unfertilized eggs also don't have any grey markings.

If you have mouth-brooding Betta, their eggs will be somewhat bigger and take longer to hatch than standard Betta eggs. Mouth-brooding males keep the eggs in their mouths until the fry is released, unlike normal male Betta fish. On emerging, they acquire a yellow color which darkens over time.

What Do Betta Fish Eggs Look Like?

Betta fish eggs are different than other types of eggs because they're attached to the bottom of the tank water, usually dead center at one of the top corners to make their way around corners. The majority will hatch within 36-48 hours after being laid. But if you don't see anything at all, there could be a few explanations for this:

The eggs might be dead and unable to hatch. If you notice a change in the eggs color, size or shape, they might not be viable so do keep an eye out. The male may have eaten the eggs as there is no sign of them after he has fertilized them (this happens often). You can read about it here in this article.

The tiny white balls are Betta fish eggs. The eggs are not completely round, but have an oval uneven shape. Mouthbrooding Betta fish's eggs are larger, ranging from 2 to 3 millimeters long and taking longer to hatch. They will swallow slightly and become increasingly yellow while the eggs develop.

How to Tell if Betta Eggs Are Fertilized by Its Color?

Fertilized Betta eggs look like tiny, oval-shaped white balls in an aquarium. The male Betta is responsible for everything from fertilization to raring, but the eggs are laid by the female. Betta fish can lay 30 to 40 eggs in one go, and in some cases, up to 500 eggs.

What Do Unfertilized Betta Eggs Look Like?

Betta eggs are initially white. When they are fertilized, though, they will become black dots with embryonic development inside them. They will turn fuzzy if they stay white. These eggs are infertile.

What Happens to Unfertilized Betta Eggs?

When the eggs hatch, females select the highest-quality eggs and put them in betta bubble nest. They are not fertilized, therefore they will transform into fungal organisms that must be removed.

However, to have fertilized eggs, you need to have fertile parents. But, it is not necessary for every egg in the aquarium to be fertilized. Sometimes, even if parents are fertile but have no mating exerience, they can produce unfertilized eggs.

Do Bettas Eat Their Fry and Eggs? 

In cases of unsuccessful spawning or unfertilized eggs, betta fish will occasionally consume their eggs. It's uncommon for betta fish to eat their young (fry) when they're not hungry (aggressive). When a betta is extremely hungry or aggressive and has no other choice, it'll only eat its fry.

Since the male betta fish is only interested in fertilized eggs, it frequently consumes the unfertilized and destroyed eggs. Betta fish have been observed consuming the fertilized eggs in rare circumstances, however. It's possible that this is stress eating. So always try to keep your fish in a calm and peaceful setting to avoid any issues.

Sometimes even though eggs laid are in perfect condition, it won't survive because the female Betta fish would eat them. That is why male Bettas are required. The male Betta builds a bubble nest for the prospective fries as soon as the egg emerges from its egg hole. This bubble is called milt and helps fertilize the Betta eggs.

How Many Days Does Betta Fish Eggs Take to Hatch?

In about three days, the baby betta fish will hatch. Male betta fish will watch and remain below the bubble nest as the eggs fall out once they hatch. The newborns known as "fry" are quite tiny at this point. The parents will not care for the youngsters; instead, they'll seek their own food as they grow.

The time it takes for your eggs to hatch is determined by a variety of things, including:

Temperature: The warmer the Betta fish water, the faster the eggs will hatch. Because your metabolism is faster and digestion happens more rapidly in warm water, the rate at which your eggs hatch is significantly affected. Eggs can hatch in 24 hours if kept at 75°F, but eggs stored at colder water temperatures might take more than 3 days to develop.

Number of Betta Fish Eggs: More eggs will take longer to hatch, as they are competing to be hatched first.

Health of you Betta Fish: If either parent is sick or weak, it can prolong egg hatching time.

Improper Water Conditions: Lowering the ammonia level, nitrite levels and increasing dissolved oxygen will ensure a healthy environment for the eggs. Dirty water may have a major impact on the growth rate and health of Betta eggs. Betta eggs in filthy water may result in some, or even all, of your eggs being hollowed out or dying. Betta eggs on the bottom of the tank are unusual, but if tank water is dirty above a tolerable level, they'll sink to the bottom, which isn't a good indicator. The fish's feces in the aquarium might lead to an increase of ammonia levels, which are harmful to the fish. In addition to ammonia build-up, the general dust, uneaten food and hazardous chemicals from the air mingle with one another inside the water to form a filthy environment.

Species: Different Betta fish species can produce eggs that take different amounts of time to hatch. The average is two to three days, however. The eggs of bubble-nesting betta fish hatch much faster than those of other mouthbrooding types. Some Betta species, such as the Betta macrostoma, can take up to a month to hatch and swim free!

Hatching 1


What Happens After Hatching?

The Betta fries don't become self-sufficient right away. They feed on the yolk sack for a day or two after being released, and if they fall out of the Betta nest with eggs, their father is responsible for catching them and returning them to their proper location.

The fry grows, learns to swim, and stops relying on its father after another day or two. To keep the water quality in the grow-out tank at an excellent level, you'll need to conduct daily water changes starting when the fry are about two weeks old. Some breeders advice partial water change(25%) twice each week, while others recommend performing smaller amounts of water every day.

How Long Do Betta Fish Live?

It is very difficult to say how long a betta will live on average as they have a wide range of lifespans. Some betta fish have been known to live for more than five years however.  Their usual lifespan is 2-5 years.

How Many Eggs Do Betta Fish Lay?

The average number of eggs in a batch is 30 to 100, but females can produce up to 400 eggs in one batch. Mouthbrooding bettas lay far fewer eggs, generally 10 to 20 per batch, because the male broods them in his mouth.

The number of eggs a betta female lays is determined by a variety of factors, including:

The size/age of the female

Betta fish reach sexual maturity at a age of 2-3 months, but it is better not to breed them at a young age. It takes a lot of energy and is more hazardous for a little female to produce eggs. The ideal time to breed your Betta is when she reaches full size and is comparable in size to the male.

If the female is too large for the male, he might have a tough time clamping around her when spawning and pushing the eggs out and fertilizing them.

Smaller females will lay considerably less eggs than larger and older ones because they don't have the capacity to carry and hatch all of them, necessitating energy allocation in growth.

I believe that female maturity is most efficient around one year old. Age is not so important; if your 3-month-old female is already fully grown, she's safer and better for it. The same goes for smaller older females.

I recommend spawning your fish between the ages of 8 months and a year. My females are fully grown at around 6 months old, making this the ideal time to spawn them. You now know the maximum adult size of your betta female, as well as when she has matured enough to produce good eggs and can handle the male. Female Bettas are fertile throughout their lives, although they become less so as they get older.

Conditioning of the Female

One of the most frequent reasons for small spawns is that the female isn't sufficiently conditioned before spawning. The pair develops a desire to spawn during conditioning, and the female begins to produce lots of eggs. The higher your pair's conditioning, the greater their chances of success are, as well as how many eggs they can create. 

Providing the pair with high-protein, live and frozen foods on a daily basis can help to stimulate breeding behavior and egg production. To encourage breeding activities and egg productivity, show the pair to each other on a regular basis.

Although bettas are capable of producing a large number of eggs, it is uncommon for hundreds to develop into viable fry. If the spawn is big, the male will usually eat a portion of them in order to ensure that he can give the best care to the rest of the fry. If your male isn't experienced, there's a chance a lot of them won't be fertilized, so he'll eat them.

Experience of the Female

The average number of eggs a female will lay, on average, is 65 to 90 eggs. The more experienced the female is, the better her chance of spawning and producing more eggs. When your male and female are both skilled, there's a greater possibility that the eggs will be fertilized and that the fry will survive.

How to Know if the Bubble Nest Is Fertilized?

When you spot white speckles in the bubble nest, it indicates that the eggs have been fertilized and will hatch within 24 to 36 hours. To prevent the male and female from devouring the fries when they emerge, remove them from the betta fish tank.

When you notice black spots, it's an indication that the fry's are out and consuming nutrients from the bubble nest. This is when you should prepare baby brine shrimp or daphnia for the newborn betta fries.

After How Much Time Can a Female Fish Lay Eggs?

The female Betta fish is one of the most productive aquarium pets. Every two weeks, they deposit eggs in your tank, so you'll be drowning in fries in a couple of months. However, this period may differ from fish to fish.

What Are the Signs and Symptoms of an Expectant Betta?

The female betta's abdomen will become swollen. After she has released her eggs, she can look like she ate a large dinner, but this is just one of the symptoms of an expectant mother.

If you notice a round white spot on your female Betta fish's stomach, she is probably carrying her eggs. This organ is known as an ovipositor and is located between her ventral fins. The ovipositor is where your female Betta will soon discharge her eggs from.

When the eggs are almost ready to hatch, you can see them through the skin of her belly where they stick out like small white grains on black bread. She will be very sensitive to your touch at this time and may flare or even attack if you try to move her around too much. If this happens, be very gentle with her so as not to hurt yourself trying to remove some eggs for hatching purposes.

At What Temperature Do Betta Fish Mate?

Bettas love tap water temperatures between 76 and 80 degrees Fahrenheit (24 to 27 degrees Celsius). This is the perfect temperature for their spawning. Make sure to have a heater if you live in a cold area, as well as establish an artificially lighted area of your room where the fish can reproduce.

Males will be especially territorial at this time and may attack each other. If your male attacks his female, you should separate them until they calm down. Make sure that she has plenty of hiding places so that she feels protected.

After a successful spawn, remove the parents from the tank water immediately or they might eat their own fry or even those of another betta pair after mating with them too! A new home must be provided for each couple because pairs are very territorial and will kill any others who invade their territory.

How Do I Know When My Male Betta Is Ready to Mate?

A male betta fish will construct a bubble nest if he is ready to breed. These bubble clusters will be floating at the top of the betta fish tank and look like a group of tiny bubbles. Male betta fish will often remain beneath the nest while they wait for a female to mate with them.

Can a Betta Fish Lay Eggs Without a Mate Present?

Female betta fish are unable to lay eggs without the help of a male. Male fish fertilize the eggs and press the lower body of the female fish, causing the eggs to emerge from its body while breeding.

Is My Female Betta Fish Pregnant or Just Fat?

A female betta fish is pregnant if she has a white rounded abdomen. When they are about to hatch, the eggs will stick out of her body like tiny white grains that look like rice. If your female betta fish has a swollen belly, you should introduce it to the males' tank as soon as possible. This way they can breed and you will have a lot of baby bettas in a few days!

betta breeding

How to Set Up a Breeding Betta Tank

No 1. Create a breeding tank with five inches of water and no substrates to keep the young fish company. You'll need a slightly larger aquarium for breeding. A 10-gallon larger tank is ideal.

Here Are Some of the Things You Would Need for Betta Breeding:

  • Breeding Aquarium: 10 Gallons
  • Fry Rearing Aquarium: 30+ Gallon
  • 5 Gallon Aquarium Kit
  • Sponge Filter
  • Air Pump
  • Airline Tubing
  • Air Regulator
  • Heater: 25w

No 2. Make sure that it is clean and fresh water and is completely cycled and at the proper temperature. The betta breeding tank should not have any substrate, but you will need to provide plenty of hiding places in the form of leafy plants. The breeding Betta fish tank should have a sponge filter or an air stone, as well as some floating aquatic plants like Java Moss for the female betta and fry to hide in.

No 3. Select a Healthy Breeding Pair.

No 4. Keep the female betta from breeding with other males until both fish are mature enough to breed.

No 5. Wait for the male to construct his bubble nest. These bubble nests will float on the top of the tank and form a cluster of tiny bubbles. Male betta fish will frequently remain under the nest while waiting for a female to mate with it.

How to Choose Your Breeding Pair of Betta Fish

  • Because fertility drops dramatically after their first year, choose bettas that are between 4 and 11 months old.
  • Look for fish that are very active, bright and vivacious! They should be inquisitive, responsive to their surroundings, and have a voracious appetite. Avoid getting bettas that appear listless, dull, or unwilling to eat.
  • Look for the brightest, most colorful male betta. Male fish with a deep, rich color are more likely to be healthy and free from parasites than pale-colored fish. 
  • Female bettas are typically less colorful and more drab in appearance than the males, so look for females with a lot of energy and overall health rather than their hues.
  • Bettas should be picked from aquariums that are well-maintained, with no missing scales or patches of fungus on their bodies. They should be plump yet not fat, and their fins should be smooth and free of jagged edges or cuts. If your fish is ill, its split fins are a possibility.
  • It's probably best to match your breeding bettas of adequate size, so select a female that is only slightly smaller than your male betta. Nonetheless, avoid selecting a female who is larger than your male; this type of combination frequently fails.

What Does Betta Fish Look Like at Day One?

Cute little betta fish are miniature replicas of their parents at birth. They are typically brown in color. They will also have the big round eyes of their parents with small black spots on it.

Final Thoughts:

In this post, we've gone through the process of determining if Betta eggs are fertilized. Let's pull everything together in a tiny package for you:

If the eggs are white with a grey dot in the center, and grow gradually, they have been fertilized. The female Betta fish is capable of producing eggs without the assistance of the male fish.

The male Betta is in charge of fertilizing the eggs and defending them. It might take one to three days for an egg to hatch. Every two weeks, a female fish may lay eggs. When a female fish's colors change, it means she is ready to mate.

You've learned everything you need to know about Betta eggs fertilizing and hatching in this post, so now that you've gone through it, you should be able to tell the fertilized eggs from the unfertilized ones, as well as anything else regarding the process!

Sarah Robertson


I am a passionate blogger who also happens to be a fish keeping enthusiast. Writing about my hobby is something that I absolutely love to do, and it's no secret that my chosen topic is always centered around fish keeping.

Sarah Robertson

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