Goldfish Laying Eggs – Signs & Behavior

Beloved by both well-versed aquarists and beginners, goldfish are among the most popular species of freshwater aquarium fish. However, goldfish remains quite enigmatic from one standpoint— reproduction.

It’s notoriously difficult to breed this species in captivity. So, most people don’t even bother to understand the reproduction cycle in goldfish.

But if you’re reading this article, you’re probably interested in this topic. Whether you’re trying to breed your goldfish or you suspect some of your goldfish might be “pregnant”, this article is for you.

We’ll be covering everything you need to know about goldfish egg-laying. So, keep reading to find out more about goldfish eggs and reproduction!

Do Goldfish Lay Eggs or Give Birth?

There are two types of fish out there. First, you have livebearers. Then, there are egg layers. Goldfish belong to the latter group.

This means that goldfish lay eggs, lots of them. A female goldfish can lay hundreds of eggs with each batch.

But that doesn’t mean you’ll get a tank full of hundreds of goldfish fry. The eggs must also be fertilized after leaving the female’s body. Shortly after the female goldfish releases the eggs, the male goldfish will release milt for fertilization.

Then, the eggs become “viable”. Because of how reproduction works in egg-laying fish, it’s more difficult to achieve successful breeding in goldfish.

A male goldfish won’t be able to fertilize all the eggs released by the female. Then, some of the eggs might get eaten by other fish in the tank. Some of the eggs just get damaged due to poor or unsuitable water parameters.

Just know that the number of fry will be a lot smaller than the number of eggs being laid.

I should also mention that goldfish are seasonal breeders. The water temperature, feeding schedule, and other environmental factors must closely mimic natural seasonal shifts.

This will encourage the goldfish to breed as they would in the wild. They just need a little push. Goldfish are worlds apart from livebearer fish like guppies, which can breed successfully at any time.

When do Goldfish Lay Their Eggs?

In captivity, female goldfish can develop a batch of eggs every few months. A few times a year, your goldfish might be carrying anywhere between a few dozens to hundreds of eggs.

The eggs are fully developed and ready to be released after roughly 3 weeks in the female’s body. But the right conditions must first be met.

Without the right environment, the female won’t release the eggs. In some cases, they might not develop eggs at all!

Goldfish are sensitive to water temperature fluctuations. You have to imitate the seasonal changes that take place between winter and spring.

It might seem difficult to believe, but in the wild, goldfish know exactly when winter is close to its end.

When temperatures start to slowly go back up to 60°F or higher in early spring, female goldfish start developing eggs.

They’re ready to release the eggs when the temperatures reach 68°F or higher. The goldfish will lay eggs multiple times a week throughout the warm months of spring and summer.

The entire spawning process usually takes 3-4 hours and happens in the early morning.

Where do Goldfish Lay Their Eggs?

Goldfish aren’t a nesting species. They aren’t picky about where they lay their eggs. If you let them spawn without intervening, you might end up with a bunch of eggs scattered all over the aquarium or pond.

But there are some spots you should check first.

A lot of the eggs will be stuck to aquatic plants, roots, and other fixed objects like decorations or driftwood. The eggs might also stick to the substrate. If we’re talking about a pond, the goldfish tend to lay their eggs closer near the edges.

Goldfish eggs are very sticky and they get instantly attached to wherever they land. If you get eggs on plants or the substrate, they will be a major pain in the butt to remove. This can get messy since goldfish just scatter the eggs everywhere while spawning.

For these reasons, I recommend using multiple spawning mops. They’re super cheap and made out of acrylic yarn. They won’t soak up any water, and the rough texture makes the eggs stick near instantly. These mops should catch most of the eggs and save you a lot of tedious cleaning later on.

What do Goldfish Eggs Look Like?

Goldfish eggs are very tiny. They’re like perfectly round gelatinous bubbles and smaller than a grain of rice. The color varies a lot and can be white, see-through, orange, or golden, depending on the viability of the eggs.

Right after being released, the eggs appear yellow to light orange. If the eggs remain unfertilized, they will turn white. Once fertilized, the eggs will turn a more see-through golden brown within a few days. Fertilized eggs also have one black dot in the middle.

Given the small size and neutral colors, you might easily overlook them. They don’t stand out against lighter-colored substrates and decorations. That’s all the more reason to use a spawning mop to catch the eggs before they get scattered.

How Many Eggs do Goldfish Lay?

Maybe goldfish aren’t prolific breeders like guppies. But they can lay lots and lots of eggs! For a female goldfish, laying a few hundred eggs isn’t out of the norm.

But the exact number of eggs per batch will depend on a few factors such as environmental conditions, feeding, and the age of the fish.

A young, well-fed goldfish in a warm water aquarium will be at its full potential. If all the right conditions are met, you can expect your goldfish to lay even over 1,000 eggs at a time!

Now that’s a lot of eggs. And notice that I mentioned “at a time”.

When carrying eggs, the females will release them periodically over the spawn of a week. By the end of it, the total batch might contain more than 10,000 eggs! Whew! I’m really glad not all of them can hatch, to tell you the truth.

I have no idea what I’d be doing with so many fish.

Of course, these are just the top numbers. Goldfish can also just release a few hundreds of eggs at a time and have way smaller batches. Not that a couple of hundreds of eggs is something to scoff at!

Can Goldfish Lay Eggs Without a Male?

Yes! Female goldfish can and do lay eggs even without males in the tank. That’s because females produce and release eggs regardless if there are males available to fertilize them.

If the fish are well-fed and the temperature is high enough, the goldfish will produce eggs. Once these eggs are fully-formed, they must be released.

Holding them for too long can cause issues for the female fish. Shortly before or right after releasing the eggs, the female goldfish starts releasing pheromones in the water.

If there are male fish in the tank, this would entice them to fertilize the eggs. Otherwise, well, obviously nothing will happen.

In this sense, you can say that female goldfish are similar to hens. Both can release eggs even without spawning. However, without a male goldfish to fertilize the eggs, females won’t be able to reproduce.

The unfertilized eggs will just start decomposing. Many of them will also get eaten by adult fish.

And here’s a fun fact, by the way! Male goldfish can only fertilize the eggs in the first few minutes after they’re released. Beyond that point, fertilization becomes impossible.

So, if you plan to add males to the aquarium, later on, they won’t be able to spawn until the female releases the next batch of eggs.

How to Tell the Difference between Fertilized and Unfertilized Goldfish Eggs?

The difference is hard to spot early on. It takes around 2-3 days before the eggs change color. At first, both the fertilized and unfertilized eggs will look the same. They’ll be a cloudy yellowish color.

After 2-3 days, the fertilized eggs will become nearly transparent. They usually turn to a translucent, light yellowish-brown.

Fertilized eggs also have a tiny black dot on the upper side. This is the first sign that cell division is happening. The fry is starting to develop! As time goes on, you’ll see a light-colored shape forming around this dot. This is the body of the young fry, which is almost ready to hatch.

What about the unfertilized eggs? By the second day, the unfertilized eggs are clear white and they stand out more than the fertilized eggs. By day 2-3, the unfertilized eggs start decomposing.

You might see signs of fungus growing on them. However, you shouldn’t try to remove the eggs as you risk spreading the infection to the healthy eggs.

How Long Does It Take for Goldfish Eggs to Hatch?

It all depends on the environmental factors the eggs are exposed to. Goldfish eggs can hatch in as little as 2 days.

In some cases, it might take up to 10 days for the fry to come out. But the average time is around 3-7 days.

In general, the higher the water temperature, the faster the eggs will hatch. Water temperature also affects the subsequent development of the fry. Of course, there’s an upper limit to how warm the water can get before the fish suffer from low oxygen.

In general, the water temperature should be close to but no higher than 75°F. This encourages both spawning and faster hatching. Oxygenation is also very important for hatching.

Goldfish eggs need oxygen-rich water to develop and hatch. This is another reason why the temperature must not climb too high.

If 10 days have passed and nothing happens, it’s safe to assume that the eggs are either unhealthy or infertile. Since female goldfish lay so many eggs at once, some of them are bound to remain unfertilized. Of the eggs that do hatch, you can expect over 50% of the fry to not make it into adulthood.

Do Goldfish Eat Their Eggs?

Unfortunately, they do. If you’re trying to breed as many goldfish as possible, keeping the eggs in the main tank will go against your plan. Goldfish, like most other fish species, have 0 parental instincts.

Once fertilized, the eggs and the future fry are left unprotected. The newly-hatched fish have to fend for themselves.

It’s not clear why goldfish eat their eggs (and sometimes the fry). Maybe they mistake the eggs for tiny flakes, or they just don’t care. And they eat both the fertilized and unfertilized eggs.

To save as many eggs as possible, you’ll have to keep them in a separate tank. Sadly, goldfish aren’t livebearers, and fertilization happens after laying the eggs.

You can’t simply move the female to a different tank to give birth. You might have more success keeping an egg-carrying female and 1-2 males in a separate tank until they spawn.

Then, simply remove the adult fish and continue looking after the eggs. You can also place spawning mops in the main tank. Once the eggs are attached, you can remove the mops and place them into a different tank.

How do You Care for Goldfish Eggs?

There are multiple things to keep in mind when looking after goldfish eggs. Most of them we’ve already touched upon. But we’ll cover everything once again in more detail.

Here’s what to do for the healthiest batch of goldfish eggs:

– Prepare a Safe Environment

The very first thing you want to do is prepare a safe environment for the eggs. The eggs should be in a separate aquarium, away from adult goldfish that can eat them. You can put a breeding pair in a new tank and let them spawn there. Then, move the adults back to the main tank.

Or you can let the fish spawn in the main tank. There, use some spawning mops to catch the eggs. Be very careful when moving the spawning mops to the new tank! The transition should be quick.

Don’t let the eggs dry out by waiting too long! Also, ensure the water parameters are as close as possible between the tanks. Just like fish can suffer from shock, so can the fragile eggs!

– Monitor The Water Parameters

Once moved to a new tank, you’ll have to keep an eye on the temperature and pH. Any swing in these water parameters can be detrimental to the eggs. You’ll need a good filter and a heater to keep the parameters constant.

Again, the water temperature should be close to but no higher than 75°F. This is the ideal temperature that makes the healthy eggs hatch in less than 4 days.

Water pH should be stable, between 7.0 and 8.4. Any drop under 7.0 pH means the water is turning acidic due to harmful bacteria.

– Don’t Forget Aeration

Goldfish eggs need plenty of oxygen to develop properly and hatch as quickly as possible. To keep the water oxygenated, make sure to include plenty of plants, as well as a bubbler or an air stone.

– Watch Out for Fungus

Infertile eggs start rotting very quickly. They will look fuzzy due to the fungus growing on them. This fungus can spread to the healthy eggs, killing them in the process. However, removing these bad eggs by hand is a bad idea.

The risk to spread the fungus in the water is too high.

Instead, you can do two things. First, add Methylene Blue to the water. The right ratio would be 10 drops of 1% pure Methylene Blue for each 2 gallons worth of aquarium water. This will keep the fungus at bay.

Don’t be concerned if your water turns blue. This is completely normal.

The second thing you can do is to add a couple of cherry shrimp to the aquarium. These little guys gorge themselves on decomposing plant matter and other dead organisms, including unfertilized fish eggs.

They’ll take care of the putrefying eggs before the disease can spread to the healthy eggs.

Conclusion

Goldfish are egg-laying, seasonal batch breeders. It’s quite difficult to breed them in captivity.

You’ll have to provide the right type of environment. And this includes gradual temperature changes that mimic the natural shift between the colder and warmer seasons.

But as difficult as it is to breed them, at least they’re very prolific! A female goldfish can lay upwards of 1,000 eggs at once, and as much as 10,000 eggs per breeding season!

If you manage to get your goldfish to spawn, you should pay extra attention to the fertilized eggs. They require constant high-temperature water, good aeration, and anti-fungal medicine.

If you follow the steps outlined in this article, you should be able to save as many eggs as possible! With the right setup, you can expect the eggs to hatch in as little as 4 days.