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How Long Does It Take For Betta Eggs To Hatch?

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Betta fish are fascinating creatures, especially when they breed. I won’t forget the first time I saw a batch of betta fish eggs inside their bubble nest. Obviously, that came with many questions, the first being when they are expected to hatch.

It typically takes between 24 to 72 hours for betta fish eggs to hatch. That is the expected period given the proper water parameters, including a temperature of 78 to 80 degrees F. The eggs of mouthbrooder bettas take longer to hatch, approximately one month.

As we move forward, I will elaborate on how long it takes for betta fish eggs to hatch. Then, I’ll discuss why they may not hatch after three days and what steps you should take if that happens to you.

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.

How Long Does It Take For Betta Eggs To Hatch?

When a female betta generates eggs, the male fish has to squeeze them out by wrapping its body around the mother. The male betta is also responsible for fertilizing the eggs.

Once the eggs are fertilized, the father will carry them to the bubble nest, watching over them until they hatch, which takes two to three days.[1]

Many of the standard egg layers in aquariums follow a similar schedule. It can take Bristlenose Pleco eggs ten days to hatch. But Cory catfish, gourami, tetras, and the like fall within the same 2-5-day period.[2]

Mouthbrooder bettas are unique, as it can take their eggs a month to hatch. But mouthbrooder eggs are easy to spot. The eggs of an ordinary betta fish are just 1mm in size. Additionally, they are more oval than round.

Mouthbrooding betta eggs are two or even three millimeters in size.[3] The male fish keeps the eggs in his mouth, which is why the female only produces 10 or 20 eggs at a time. This is in sharp contrast to the 40, 50, or even 500 eggs an ordinary betta can generate in a given spawning session.

Mouthbrooder eggs are safer because the betta fish protects them at all times within its mouth. The father’s gills provide the offspring with all the oxygen they need. Though, the male betta is also more vulnerable to predators because the eggs in its mouth are a burden.

Why Don’t My Betta Fish’s Eggs Hatch In Time?

Unless you have a mouthbrooder betta in the tank, an ordinary betta’s eggs shouldn’t take more than three days to hatch.

If your male betta’s nest is still intact, but you can’t see any new fry in the aquarium after three days, you have several factors to concern:

1. The Eggs Are Not Fertilized

The eggs cannot hatch unless the male fertilizes them. Fertilized eggs are white and oval-shaped.[4] As they mature, you will notice a gray spot in the center. Unfertilized eggs don’t have this gray spot. They remain white instead.

Don’t expect the male betta to fertilize all the eggs the mother produces. It will neglect a few of them. This shouldn’t concern you because it happens in every tank. However, if all the eggs in the aquarium are unfertilized, you have a problem.

If you’re lucky, the father is simply inexperienced. In other words, with enough practice, it will learn to fertilize the eggs it squeezes out of the female betta.

But you shouldn’t ignore the conditions in the tank. Stress can disrupt the breeding process, forcing the mother to generate eggs the father will never fertilize.

Common sources of stress include poor parameters, high ammonia concentration, and food scarcity, to mention but a few. You can resolve this issue by improving the conditions in the tank.

These are the ideal water parameters for betta fish eggs:

  • Temperature: 78-80° F (25-27° C) 
  • pH: 7.0-7.2 
  • Hardness: 5-20 DH (70-300 ppm) 
  • Ammonia: 0 ppm 
  • Nitrties: 0 ppm 
  • Nitrates: <20 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, although it is highly accurate and lasts for eight hundred measures.

I also recommend getting the well-known Seachem Prime Conditioner (link to Amazon). Even if your water parameters are correct, this product will prevent them from going wrong in the future. It is definitely worths the investment.

If you still have unfertilized batches of eggs despite the improvements in the aquarium’s conditions, your fish are probably infertile.

Fortunately, the male tends to eat the unfertilized eggs it encounters in the water. But if this situation persists, you need a new breeding pair.

2. The Eggs Have Been Infected With Fungus

If the eggs have fuzzy growths, your tank has fungi. Fungi are a menace that frequently threatens unfertilized eggs because they are so vulnerable. People think that a fungal infection will prevent their betta eggs from hatching.

However, that is not a guaranteed outcome. Your eggs may hatch only for the fungus to jump to the fry. The male fish will do what it can to protect its offspring. However, it isn’t immune to this threat.

Fungal infestations can compel amateur aquarists to discard their entire batch of eggs to prevent the fungus from spreading. But if you can’t eliminate the source of the fungus in the tank, future outbreaks may destroy every batch of eggs your bettas produce.

One of the most problematic species is Saprolegnia. The growths look like cotton, and if you’re lucky, they will only terrorize the dead organic matter in the water. Living eggs have antimicrobial enzymes that can defend against Saprolegnia.[5]

But the eggs are not invincible, and some of them may succumb to the fungus. The death of an egg does not end the lifecycle of the fungus. It will simply jump to the next egg in the bubble nest.

Betta eggs are fortunate because Saprolegnia tends to thrive in low oxygen environments. Some aquarists fight the fungus by placing air stones in the vicinity of the eggs.

But betta fish house their eggs in bubble nests near the surface. Therefore, oxygen deficiencies are not a problem for these creatures. Then again, even if the eggs can repel the fungus, the attack can still leave them vulnerable to various parasites.

You cannot keep fungi out of an aquarium. But you can protect your betta’s eggs by creating a strict maintenance routine. You can also experiment with chemical products like malachite green and formalin.

What Should I Do If The Eggs Don’t Hatch?

If the eggs have refused to hatch despite your best efforts, remove them. You don’t have to do this right away. The male bettas will eat all the unfertilized eggs, but they typically leave the viable ones alone.

If the father is still protecting the eggs, wait another day or two. You don’t lose anything. The father will continue to eat the eggs if they are indeed dead.

If some eggs start hatching, wait for this process to play out. You don’t have to separate the unfertilized eggs from their fertilized counterparts at this stage. The presence of dead eggs doesn’t prevent the healthy ones from hatching.

Once all the healthy eggs have hatched, you can take steps to eliminate the dead ones. If it took three or more days for the healthy eggs to hatch, the dead ones should have developed fuzzy growths by this point.

If the bettas are mating in a community tank, the other adult fish can eliminate the dead eggs for you. But if you don’t have enough aquatic creatures in the aquarium to eat the eggs, remove them manually.

Like other dead organisms, the dead eggs will decompose, increasing the ammonia concentration and harming the tank’s inhabitants.

Some people intentionally ruin the conditions in aquariums to prevent eggs from hatching. They adjust the temperature and pH to create a hostile environment for betta eggs.

While this tactic can work, you still have 50 – 60 eggs to remove from the tank. Though, if you leave the female fish in the breeding tank, she may eat all the eggs before you can get to them.

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.


Betta fish eggs are expected to hatch within 72 hours. To ensure they hatch in time, I suggest testing the water parameters. Aim for a temperature of 78 to 80 degrees F and a pH of 7.0 to 7.2.

If they don’t hatch after three days, you should wait a little longer. Observe the eggs carefully and see if they have a fuzzy growth upon them. If they do, they are probably infected with fungi, and you should get rid of them.

But ultimately, some eggs may still hatch at this point. So you should be patient. It is also worth mentioning that the male betta will eat unfertilized eggs while taking care of the valid ones. 

If you see no change, you should probably toss them out. Rotten eggs will interfere with the water chemistry. They will produce ammonia and make the water more acidic. Ultimately, they will make it difficult for the fish to breathe appropriately.