What Do Neon Tetra Eggs Look Like? A Detailed Picture Guide

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Neon tetra eggs are fascinating to encounter in your tank. I was pretty excited when I first saw them.

However, I had to determine whether these were 100% neon tetra eggs or if a snail or another shrimp were responsible for this batch.

In this article, I will detail what fertilized, unfertilized, and fungus-infected neon tetra eggs look like and what you should do with each one.

Let’s get started.

What Do Neon Tetra Eggs Look Like?

After the female neon tetra lays her eggs, the male fertilizes them by releasing sperm into the water. After the eggs are scattered, you can observe these changes:

1. Fertilized Neon Tetra Eggs

  • Coloration: Fertilized Neon Tetra eggs typically exhibit a clear or slightly opaque color. The eggs seem somewhat glossy due to the protective mucus layer on the surface.
  • Size and Shape: The fertilized eggs are tiny, usually about 1mm in diameter. They are round and look like small beads or pearls.
  • Egg Clustering: These eggs are often found in clusters or groups, sticking together on plants or on the substrate of the aquarium.
  • Visibility of Embryos: As they develop, the embryos inside the eggs become increasingly visible, appearing as tiny dark spots or streaks.
  • Overall Health: Healthy, fertilized eggs have a distinct look that’s different from unfertilized or infected ones. They exhibit no indications of color change or infection by fungi.

This is what you should do if you identify those kinds of eggs in your tank:

  • Step 1: Carefully observe the eggs to ensure they are indeed fertilized. Look for the distinct clear or slightly opaque color and tiny dark spots indicating the embryos.
  • Step 2: Sustain a consistent aquarium environment by maintaining suitable temperature (approximately 77°F) and pH levels (ranging from 6.0 to 7.0).
  • Step 3: Reduce light exposure to the eggs, as intense light can harm the developing embryos.
  • Step 4: Regularly clean the tank without disturbing the eggs. Eliminate any debris or leftover food that could potentially contaminate the water.
  • Step 5: Keep a close watch on the eggs for indications of hatching, which typically takes place within 24 to 36 hours following fertilization.
  • Step 6: Once the eggs have hatched, feed the fry with infusoria or liquid fry food, since they cannot eat regular fish food.
  • Step 7: Continue monitoring the fry and gradually introduce them to regular food as they mature.

Also Read: Neon Tetra Eggs 101

2. Unfertilized Neon Tetra Eggs

  • Color and Appearance: Unfertilized Neon Tetra eggs tend to turn a cloudy, milky white. They lack the clear or semi-transparent appearance of fertilized ones.
  • Lack of Visible Embryos: In contrast to fertilized eggs, these eggs do not show any signs of developing embryos. They remain uniform and devoid of any dark spots.
  • Size and Shape: While the size and round shape may remain consistent with fertilized eggs, the surface can become slightly irregular due to lack of development.
  • Risk of Infection: Unfertilized eggs are particularly vulnerable to bacterial or fungal contamination, resulting in a fuzzy, moldy appearance.
  • Egg Clustering: Although unfertilized eggs can also be found in clusters, these groups may appear less organized or more loosely connected than fertilized ones.

If you suspect that your neon tetra’s eggs aren’t fertilized, follow these steps:

  • Step 1: Identify unfertilized eggs by their milky white appearance and lack of visible embryos.
  • Step 2: Carefully remove the unfertilized eggs from the aquarium to prevent them from causing water pollution.
  • Step 3: Dispose of the eggs responsibly, ensuring they do not contaminate any water bodies.
  • Step 4: Clean the aquarium thoroughly to remove any remaining unfertilized eggs and prevent potential fungal contamination.
  • Step 5: Monitor the remaining eggs and fish for signs of stress or disease, which could have resulted from the presence of unfertilized eggs.
  • Step 6: Adjust the conditions in your aquarium to increase the likelihood of successful fertilization in the future.
  • Step 7: Continue regular maintenance of your aquarium, paying special attention to water quality, temperature, and pH levels.

3. Fungus-Contaminated Neon Tetra Eggs

  • Apparent Fungal Growth: Eggs infected with fungus will manifest a unique fluffy or cotton-like texture, typically of a gray or white hue.
  • Change in Color: Beyond the visible fungal growth, the eggs themselves may undergo discoloration, turning from a clear to a cloudy or milky look.
  • Transparency Reduction: Such eggs forfeit their transparent quality and turn opaque, which renders spotting any embryo development impossible.
  • Alterations in Size and Form: The eggs under fungal assault might expand or become misshapen, showcasing an irregular form due to the fungal intrusion.
  • General Health: The overall appearance of the fungus-infected eggs will be unhealthy, often in the midst of cloudy, degraded water conditions, which could potentially jeopardize the health of the neighboring eggs and fish.

If you think that the eggs were contaminated by fungus, follow these steps:

  • Step 1: Identify fungus-contaminated eggs by their fluffy, white or gray appearance and the lack of visible embryos.
  • Step 2: Immediately isolate the contaminated eggs to prevent the spread of the fungus to other eggs or fish.
  • Step 3: Dispose of the infected eggs responsibly, ensuring they do not contaminate any other environments.
  • Step 4: Treat the aquarium with an antifungal medication, following the product’s instructions.
  • Step 5: Thoroughly clean and disinfect the aquarium, paying special attention to the areas where the infected eggs were located.
  • Step 6: Monitor the remaining eggs and fish closely for signs of fungal infection.
  • Step 7: Ensure proper aquarium conditions moving forward, with appropriate temperature, pH, and cleanliness to prevent future fungal outbreaks.

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

As previously mentioned, neon tetra eggs should hatch within about 24 hours. If they don’t hatch by then, this is what you should do:

  • Step 1: Keep observing the eggs for a few days beyond the expected hatching period. Sometimes, hatching might be delayed due to environmental factors.
  • Step 2: Check the aquarium conditions, ensuring that the temperature, pH level, and water quality are within the optimal range for Neon Tetras.
  • Step 3: Re-evaluate the lighting in your tank. Neon Tetra eggs need darkness to develop properly; excessive light can harm them.
  • Step 4: Verify whether the eggs have turned milky or show signs of fungal growth. These changes suggest the eggs are either unfertilized or infected.
  • Step 5: In the event of egg infection, promptly remove them from the tank to avoid contagion among other eggs or fish.
  • Step 6: In case of a persistent issue, consider consulting with a fish vet or experienced aquarist. They can help identify potential problems that are not immediately apparent.
  • Step 7: If the eggs continue to show no signs of hatching, it may be essential to remove them from the tank to prevent decay and subsequent contamination.
  • Step 8: After addressing any identified issues, try again with a new batch of eggs. Remember that successful breeding often involves some trial and error.

I also suggest testing the water after 24 hours. The following conditions are ideal for neon tetras:

  • Temperature: 72-78°F (22-26°C)
  • pH: 6.0-7.0
  • Hardness: 1-2 DH (18-35 ppm)
  • Ammonia: 0 ppm
  • Nitrites: 0 ppm
  • Nitrates: <20 ppm

To test the pH, ammonia, nitrites, and nitrates, I personally use the API FRESHWATER MASTER TEST KIT (link to Amazon).

I’ve found it to be the most accurate and cost-effective after trying many kits.

Also Read: What To Do When Neon Tetras Lay Eggs?


Here is a quick summary of what I discussed earlier:

  • Fertilized neon tetra eggs have a clear or slightly opaque color, are round in shape, and often found in clusters. The embryos inside the eggs become visible as tiny dark spots or streaks.
  • Unfertilized neon tetra eggs turn cloudy and milky white, lack visible embryos, and are susceptible to bacterial or fungal contamination.
  • Fungus-infected neon tetra eggs display a cottony or fluffy appearance, lose transparency, and may become discolored. They should be isolated and treated to prevent the spread of the fungus.
  • If fertilized neon tetra eggs don’t hatch within 24 hours, check the aquarium conditions, lighting, and for signs of unfertilization or infection. Consult a fish vet if necessary and consider removing non-hatching eggs.
  • Maintaining optimal water conditions, such as temperature, pH, and cleanliness, is crucial for successful neon tetra egg hatching and overall fish health. Regular monitoring and adjustments are recommended.