How To Tell If Mystery Snail Eggs Are Fertile? [3 Effective Methods]

Hi, this is your friend Clifton Ervin, the founder and chief editor of this site, Aquariumwolf. I completed my graduation in marine biology and became...Read more

Mystery snails are crossbred between different apple snails. If you want to breed a clutch of mystery snail eggs, you should know that these snails can also lay infertile eggs if they haven’t mated. So, how to tell if mystery snail eggs are fertile?

To understand if mystery snail eggs are fertile, you must wait two weeks. Then, the fertile eggs will grow slightly darker in color and change their texture along with their sizes. Also, you can test the fertility using a paper towel or smelling the eggs after two weeks! Fertile eggs turn moldy and irregular in size before hatching. 

However, you can’t understand whether or not the eggs are fertile till at least two weeks after the eggs are laid. Additionally, you must provide a good environment for the eggs and wait. Don’t worry! We are going to make everything easy for you. Just keep reading!

How To Check Mystery Snail Eggs Fertility

There are many signs to look for in fertile mystery snail eggs. However, the major player here is the color and texture. Fertile eggs will change from light pink to slightly darkish after two weeks they are laid.

How To Check Mystery Snail Eggs Fertility

A fertile mystery snail egg should have a small dark patch in the middle part of the egg. These eggs should look fuller and larger with different shapes than infertile clutches.

Also, the eggs may look a bit irregular. Some may look whiter or pinkish, and some eggs change their texture and become moldy. Do not get panicked by this, as the moldy look only happens just before hatching, and you should expect some baby snails!

Learn more about mystery snails.

Different Methods to Check If Mystery Snail Eggs Are Fertile

There are three different methods of checking the fertility of mystery snail eggs. The methods are: Using A Paper Towel, Smelling The Eggs, and using Appearance and Color. However, you will have to wait at least two weeks before implementing these methods!

Different Methods to Check If Mystery Snail Eggs Are Fertile

Using Appearance and Color

Appearance is the main indicator of the mystery snail egg’s fertility. When the eggs are alive, they act like they are alive. Fertile eggs changes their colors and shapes, and texture!

One to Two Days After Being Laid

The eggs are light pink just after the egg cluster is laid. When you touch these, you will realize how sensitive they are. This delicacy can only be seen till about one or two days of egg-laying. To avoid damaging them, treat the eggs with care.

After Two Days

The fertile eggs will change color and grow darker after about two days. Also, the texture of the eggs will look more rigid. The eggs will continue to throw this process for the next two weeks.

After 14 Days

After about 14 days or two weeks of being laid, the eggs are very close to hatching. You will see the eggs grow very slimy and change their color to even darker.

Also, the mystery snail eggs will change their texture and size to grow swollen. During this period, the eggs will turn dark gray, and you will be able to see a dark patch in the middle of the egg.

The eggs will not look very healthy now, but this is very natural and a very good sign. This moldy look is caused by the snail babies slowly taking the nutrition from the egg and thinning the egg sack.

After this, your mystery snail eggs should hatch. However, some eggs may hatch after three or even four weeks. The hatching period depends on many factors like temperature, genetics, nutrition in the eggs, health, etc.

Although mystery snails hatch faster if the aquarium temperature is a bit higher.

Learn more about how to care for mystery snail eggs from Blake’s Aquatics-

Smelling The Eggs

You do not need to smell the eggs very closely. If the eggs are infertile, they will start to rot after about two weeks. This rotting gives off a bad smell, similar to rotten chicken eggs.

So, if your mystery snail eggs start to smell after some time, then you should be certain that they are either infertile or damaged and that no snail will hatch from that clutch.

The fertile clutches will not give off any odor.

Using A Paper Towel

You can use this method if the complexity and texture of the eggs do not reveal anything about their fertility after two weeks.

Check Mystery Snail Eggs Fertility Using A Paper Towel

First, take a moist paper towel and carefully place the egg clutch in the paper towel. Keep the eggs on the towel for some time while keeping them moist. Then, put the egg clutch back where it was. Now, check the moist towel for stains or marks.

The mystery snail eggs are most likely infertile if you see any stains on the paper towel because fertile eggs do not leave any marks on moist paper after two weeks.

Now, Let’s Know About: How Newborn Snail Look Like in an Aquarium


As there is no way to check the fertility of mystery snail eggs before two weeks, you may have some questions about the whole process. Below we answered some frequently asked questions about this topic.

How should I dispose of mystery snail eggs?

Every fertile egg clutch will produce about 20 to 30 mystery snails. So, if you’re not a snail breeder, you should keep only one or two egg clutches and discard the others.

You can crush the egg clutch and flush them! Sounds cruel? We know!

Can I throw away mystery snail eggs?

No. As a responsible hobbyist, you should not throw away fertile or infertile snail eggs. You must destroy the eggs and then flush them down your toilet!

Because no matter how beautiful they are, snails -especially the larger ones are pests that destroy crops and even disbalance the ecosystem. Especially mystery snails are an exotic species imported from South America. So, they must not escape into the environment.

Do mystery snail eggs need to be underwater?

Mystery snails do not reproduce underwater! The female will lay eggs just above the water where there is enough moisture, but the eggs do not touch the water.

So, you must keep the mystery snail eggs moist if you want them to hatch. But not underwater.

Can A single mystery snail reproduce?

No. Although many other snail species can reproduce asexually, mystery snails can only reproduce by mating. So, it would help if you had at least a male and a female in the aquarium for the snails to reproduce.

However, the female may lay unfertilized eggs even without mating.

How many mystery snails can I keep in my aquarium?

Well, there are no fixed numbers. However, keeping one or two mystery snails for 5 gallons of water in the tank is advised. So, if your aquarium is five gallons, you can keep up to 2 or 3 snails.

However, if your tank is bigger, you can divide the tank capacity by five and multiply by 2. For example: for a 10-gallon tank, you can keep ((10/5=2)* 2)= four snails in the tank.


Breeding mystery snails are not an easy task. To check the fertility of the eggs, keep an eye on the coloration, texture of the eggs, and randomness of the eggs.

However, You must take care of the snails and mystery snail eggs well if you want to breed them. Also, as mystery snails lay eggs once a week, you must understand how many you can keep!

However, if you decide not to hatch the eggs, you must ensure that the eggs are destroyed and not released into the environment. We advise that you break the clutch and flush the eggs!

Hi, this is your friend Clifton Ervin, the founder and chief editor of this site, Aquariumwolf. I completed my graduation in marine biology and became an Ichthyologist. One of my favorite hobbies is aquarium keeping; therefore, I love to talk about fish keeping, breeding, food behavior, etc., and much more relevant to aquarium maintenance. I have created this site Aquariumwolf, to share my 20 years+ of experience and knowledge with all new to this journey.

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