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Why Do Betta Eggs Not Hatch? (With Practical Solutions)

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I remember how stressed I was when I realized my betta fish eggs were not hatching. I did not know why this was happening and whether I needed to take active steps to solve the problem. Fortunately, as years passed, I gained some experience in this field.

Betta fish typically don’t hatch because they are not fertilized. That is usually secondary to inexperienced, infertile, or stressed male betta fish. However, some eggs won’t hatch because they are infected with fungi, burrowing through the shell and feeding on the egg yolk.

Later on, I’ll explain what can be behind betta fish eggs that are not hatching. Then, I’ll present some practical steps you can take to resolve the issue. That includes some valuable products that I use to ensure the environment is suitable for betta fish reproduction.

Still curious? Feel free to check my complete guide on betta fish eggs. There, I discussed how to care for betta eggs, what they look like, how long it takes for them to hatch, what equipment to use, and much more.

Why Do Betta Eggs Not Hatch?

Betta fish can produce as many as 500 eggs at a time. But that doesn’t mean they will all hatch. In fact, there’s no guarantee that any of them will hatch.

Eggs are somewhat complicated. You can take steps to enhance the growth and appearance of fish fry by improving their nutrition, water quality, and stress levels.[1] You can also boost a sick fry’s survival rate if you act quickly enough.

But eggs are not living, breathing animals. They just sit there for two to three days until they hatch. You can’t force dead betta eggs to hatch by simply feeding them better food or cleaning their tank.

The male fish will protect the eggs, remove debris, retrieve them when they fall, and keep predators away. However, a male betta cannot fix an egg that won’t hatch.

The factors preventing a betta egg from hatching are not that extensive. It includes the following:

1. The Eggs Are Not Fertilized

Betta eggs cannot hatch unless a male fish fertilizes them. The genders perform different roles. While the female fish lays the eggs, the male betta has to fertilize them.

A male fish cannot produce eggs. And in the absence of a male fish, the eggs the female produced will go unfertilized. You have three factors to consider where this subject is concerned:

  • Appearance

First of all, how do you know that an egg is fertilized? Betta eggs are white at the start. But over time, they will turn brownish or yellowish while also developing one or more gray spots.[2]

If you observe the egg closely, you will see the eyes of the fry. Unfertilized eggs are white and opaque. Eventually, they will develop fuzzy growths on the shell, proving once and for all that they are dead.

Unfertilized eggs are dangerous because they will eventually rot. Rotting organisms produce ammonia, which is harmful to fish.

  • Experience

Unfertilized eggs are not a sign of a conspiracy. Male bettas do not choose to fertilize some eggs while ignoring others. It just happens.

Admittedly, factors like the water quality and concentration of toxins can affect the number of eggs the sperm will reach and penetrate.

However, even in a clean, well-maintained tank, you will find unfertilized eggs within every batch that a female betta produces. It can’t be helped, and it isn’t a problem.

Unfertilized eggs should only concern you if their numbers are much higher than usual. For instance, if most of your eggs are not fertilized, you should worry.

Some bettas are simply inexperienced, as they’ve never mated before. As such, they don’t really know what to do.

  • Water Conditions

Male bettas in a poorly maintained tank are less likely to fertilize the female’s eggs. Bettas require temperatures ranging from 76 to 84 degrees F, a pH of 6.5 to 7.5, and soft – medium hardness.[3]

I also suggest giving them a slow water flow rate, some aquarium salt (if you think it’s necessary), plenty of room, filters, and hiding spots.

Otherwise, they will fall prey to stress, disrupting the mating process. Poor conditions may even prevent the female betta from producing eggs. She may choose to reabsorb them.

2. The Eggs Were Infected With Fungi

Fungus is common in aquariums. You can reduce fungal infestations, but you can’t eliminate fungi completely. Fungus is dangerous because it attaches itself to fish eggs, burrowing through the shell and feeding on the egg yolk.[4]

As you may have guessed, this isn’t good because it prevents the eggs from hatching. Fungi are more likely to target the dead eggs. This isn’t an issue because the male betta will eat the dead eggs.

However, the fungus can transition from dead matter to the living eggs in a betta’s bubble nest. Some eggs may hatch despite the presence of fungi.

But a strong infestation can destroy your entire batch of eggs. Standard solutions include formalin, copper sulfate, and hydrogen peroxide.

3. Your Betta Fish Is Infertile

Are your bettas fertile? In every batch of eggs a female betta produces, a few eggs will go unfertilized. But if the male betta has seemingly failed to fertilize all the eggs, you have to consider the possibility that the bettas are infertile.[5]

Consider the breeding pair’s history. Have they spawned successfully in the past? If not, you can blame one or two unfertilized batches on inexperience. However, if this keeps happening, infertility is the only rational explanation.

If you’re lucky, only one of the betta fish is infertile. However, it may take a while to find the culprit because you have to pair the potentially infertile parents with different fish. The culprit is the betta that fails to spawn successfully with a second fish.

But rather than identifying the infertile betta, you are better off changing both fish. Get a new breeding pair that has a history of mating successfully.

4. The Eggs Are From A Different Species

Are you sure the eggs in the tank belong to a betta fish? If you have other creatures in the aquarium, you may confuse their offspring for betta eggs.

Betta eggs are tiny (1mm), white, and oval-shaped. If you have a mouthbrooder betta, the eggs are 2 to 3mm in size.

If you’re frustrated because the eggs have refused to hatch even though several days have passed, you may have eggs from a different species.

5. The Eggs Are Consistently Eaten

If you’re annoyed because the betta keeps making eggs, but you can’t see any fry, the parents are probably eating the eggs. Male bettas are supposed to protect their offspring. But stress can compel them to eat the eggs.

They usually consume unfertilized eggs. By doing so, they actually contribute to your aquarium, as these eggs are likely to rot in the future. But sometimes betta fish eat viable, fertilized eggs.

If the water chemistry is wrong or the temperature keeps fluctuating, your betta fish will make irrational decisions to survive. Their instincts will compel them into eating their own eggs, even if this is how they reproduce.

What Do I Do With Betta Fish Eggs That Don’t Hatch?

First of all, it may be just too soon for the eggs to hatch. As I previously discussed, it may take up to 72 hours for the eggs to hatch. If this time hasn’t passed yet, you should wait a while.

Measure the water parameters while waiting. As I already mentioned, these are the optimal water conditions for betta fish eggs:

  • Temperature: 76-84° F (24-29° C)
  • pH: 6.5-7.5
  • Nitrties: 0 ppm
  • Ammonia: 0 ppm
  • Nitrates: <20 ppm
  • Hardness: 5-20 DH (70-300 ppm)

To measure the pH, ammonia, nitrates, and nitrties, I personally got the API FRESHWATER MASTER TEST KIT (link to Amazon). This one is a bit more expensive than average. But it lasts for about eight hundred measures, so it is definitely worths the investment.

I also recommend getting the well-known Seachem Prime Conditioner (link to Amazon). A few drops of this product will prevent toxins from rising in the future. It acts as a buffer, and no tank should go without it.

If the water conditions are appropriate and 72 hours have passed, you should look for signs of fertilization, as I described here. If you can’t find any, get rid of the eggs before they rot.

Follow these tips to ensure the next batch of eggs will hatch, at least partially:

  • Feed the breeding bettas well. In the wild, they eat everything from zooplankton and crustaceans to insect larvae and the eggs of other fish. In an aquarium, they will appreciate bloodworms, brine shrimp, and other protein-rich foods.[6]
  • Keep the male and the female betta in separate tanks but next to one another. If they share an aquarium, use a divider. Make sure the fish can see each other.[7]
  • Observe the fish and determine whether or not they have any interest in one another. If you notice signs of aggression, such as one betta attempting to attack its potential mate through the divider, you should think about getting another breeding pair.
  • In case the next batch doesn’t hatch as well, consider getting a new pair, as it is likely that one of your betta fish is infertile.

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

Pro tip: If your betta fish has just laid eggs, you’ll need to know what to do with the fry. For that, feel free to check my complete guide on betta fish fry.


If your betta fish’s eggs don’t hatch, first make sure 72 hours have passed, as it takes time for the fry to grow. But even after three days, you shouldn’t expect all the eggs to hatch. That is because some of them are naturally unfertilized.

To ensure that most eggs eventually hatch, stick to the water parameters mentioned above. As a rule of thumb, a comfortable environment will encourage the male betta to fertilize and care for the eggs.

But if several batches haven’t hatched at all, it could be that one of your betta fish is infertile. In this case, it is best to start with a new breeding pair.