Goldfish Eggs: Beginners’ Guide To Proper Care & Supervision

goldfish eggs
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Last Updated: July 28, 2022 by Flora Gibbins

If you have adult goldfish and are looking to raise goldfish fry, you need to familiarize yourself with breeding goldfish techniques, how to identify goldfish eggs, and how to raise healthy goldfish fry.

Fact: Goldfish lay eggs. 

But for these eggs to hatch, they need a male goldfish to fertilize them. Once fertilized, you need to maintain optimal temperature and water conditions.

How do you go about this? This article details all there is to know about goldfish eggs and raising goldfish fry.

Breeding Goldfish

two goldfish in tank

Goldfish start spawning at one year. But for best breeding results, breed goldfish when the male and female goldfish are between 2 to 5 years.

Once your goldfish are mature, encourage spawning by providing protein-rich foods to guarantee quality fish eggs. Also, maintain the water temperature between 70 and 75 degrees Fahrenheit.

The tank should include surfaces to hold the fish eggs after the female releases them. Add spawning mops, artificial spawning grass, bottom plants, floating rooted plants, or soft willow. These breeding surfaces will make it easier to move the goldfish eggs safely.

When female goldfish are ready to lay eggs, their bellies swell and have a rounder shape. Female goldfish can lay as many as 1000 eggs.

When breeding goldfish, place one female fish with two males.

This will greatly reduce the number of infertile eggs and increase the odds of the fertile eggs hatching. Male goldfish follow the female closely to lay sperm on the eggs.

As soon as the goldfish eggs are fertilized, transfer them to a fry tank. Adult fish are ever-hungry and will readily eat the eggs. So, move the breeding surfaces to a fry tank.

How To Identify Goldfish Eggs

goldfish eggs bubble like shape

It might be difficult to identify goldfish eggs if you have other fish in your tank. Their eggs resemble those of other fish species and invertebrates.

Goldfish eggs are small and ovular with a bubble-like shape. They can have white or yellow-orange colors.

Fertile eggs are usually yellow with a small, dark spot on one end that develops into eyes. After a few days, you should notice a crescent shape, which is the spinal cord, forming around the spot.

The fertilized eggs develop in 4 to 7 days, depending on the water temperature. If the temperature is maintained at 70 to 75 degrees Fahrenheit, the fry may hatch in four days. However, temperatures higher or lower than this range create health problems for the baby goldfish.

Female goldfish can lay over 500 eggs at a time. Despite the male goldfish’s effort to fertilize these eggs, not all will get the fish’s sperm. These unfertilized eggs are white or opaque and can be identified after one or two days.

Some experts recommend removing these unfertilized eggs as they can begin to decay. But in all honesty, efforts to remove these eggs may prove futile. Also, goldfish lay sticky eggs.

So, if you notice many tiny, bubble-like shapes stuck to surfaces, they are most likely goldfish eggs. Their sticky nature makes them easy to transfer to a fry tank.

How To Care For Goldfish Eggs

Once the females release eggs, it takes 4 to 7 days for goldfish eggs to hatch. During this time, these eggs are prone to scum or fungus buildup, which can significantly affect the quality and health of the baby fish.

goldfish in fish tank with aeration bubbles

You can prevent scum buildup by keeping aerating the tank water.

Aeration breaks any scum and keeps the water oxygenated. Your aeration system could include an air stone, spray bar, or an air bubbler.

Alternatively, use a paper hand towel to remove scum from the water surface. Pass the towel to collect scum and repeat this with a fresh towel.

On the other hand, use methylene blue for fungus buildup. Since it is difficult to remove the unfertilized eggs, methylene blue will prevent these eggs from accumulating fungus and spreading it to the fertilized eggs.

You can purchase this water additive from your local pet store. The general rule is to use 10 drops of methylene blue for 2 gallons of water.

Alternatively, add some shrimp to eat algae and scum in the fry tank. The cherry shrimp, for instance, can help prevent fungus without disturbing the developing fry. Shrimp promote the health of the fish eggs and prevent diseases.

Additionally, maintain stable egg hatching temperatures between 70 to 75 degrees and pristine water conditions.

How To Care For Newly Hatched Fry

Expect to see movement in the fry tank from the fourth day. Goldfish fry will start emerging from their egg shells and try to swim around.

Goldfish fries spend their first few days resting at the bottom. They also use their suckers to hold onto surfaces in the tank.

goldfish at the bottom of the fish tank

For the first three days, newly hatched fry depends on their egg yolk for nutrition.

So, do not feed them. It is also during this time that these fish will start free-swimming.

Gradually begin feeding newly hatched brine shrimp or daphnia once your fry starts free-swimming. Brine shrimp hatch in 24 hours, meaning you will have them ready as soon as the goldfish eggs hatch.

When caring for goldfish fry, avoid overfeeding. These fish are fragile at this stage. Any uneaten food will decay and cause illness, hence killing these tiny fries. Therefore, remove all uneaten food from the fry tank and maintain water quality.

Use a sponge filter to generate a gentle flow and filtrate the water. This filter will not suck in the fries and kill them.

Moreover, change 25% of the water with clean water that has the same temperature as the fry tank. Use a heater to maintain stable temperatures for the first two weeks.

You will note that not all the fries will start free-swimming. Fries that do not develop air sacs do not float to the water surface for air. Instead, they sink to the bottom and eventually die. Therefore, create a clean environment by siphoning the substrate to remove the dead fry, excess food, and infertile eggs.

Additionally, you will have a large number of goldfish fry at first. But diseases, poor conditions, and inadequate food will naturally reduce these numbers.

If you feel the fry numbers are still high, consider culling as early as two weeks. Curling gives the healthier fry better conditions and cuts down the numbers.

Here is a helpful YouTube video about culling goldfish:

What Should You Do With The Goldfish Eggs In the Tank

If you are not interested in goldfish breeding, you may feel worried if you find goldfish eggs in your tank. But, you do not have to remove the eggs from the fish tank.

Leave the eggs in the tank, and the adult goldfish will consume them all, both fertilized and infertile eggs. These eggs are a tasty protein treat for adult goldfish.

Frequently Asked Questions

Why Do Goldfish Eggs Float?

We have established that goldfish eggs stick onto surfaces. But sometimes, these eggs float. If this happens, it could be due to reduced oxygen and/or CO2 levels in the tank. This, particularly, affects tanks with many live plants. The plants absorb these gasses from the water column.

How Do Goldfish Reproduce?

Changes in barometric pressure or a storm trigger goldfish breeding in the wild. But you can replicate these conditions by gradually lowering the temperature, then raising it.

You can tell your goldfish will start to breed when the females rub their bodies against the spawning mops and remain close to the males.

Do Female Goldfish Need A Male To Lay Eggs?

No. Females lay eggs with or without a male. They will release eggs when ready. However, if a male does not fertilize them, the eggs will not hatch.

What Should I Do With Infertile Eggs?

Remember, it takes 4 to 7 days for goldfish eggs to hatch. If the eggs have not hatched in 10 days, they are infertile. The best remedy is to dispose of them.

Can I Make A Spawning Mop?

You sure can instead of purchasing it from the pet store. Use acrylic yarn as it does not rot in water. Next, soak the yarn in hot water for 10 minutes to rid of dye, chemicals, and germs. Once clean, cool the spawning mop before placing it in the tank.

Conclusion

If you maintain stable breeding temperatures in the aquarium, your goldfish can spawn all year round. But this would not be healthy.

Females can lay more than 500 eggs at once. So, if you are not ready to raise goldfish fry, do not remove the eggs from the tank. This way, the adult fish will eat them all.

However, if you want the goldfish eggs to hatch, add spawning surfaces for the eggs to stick on. Then move the eggs to a fry tank for hatching.

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