Mystery Snail – A Complete Care Guide

It’s not often that a pet comes along that is both entertaining and educational, but the Mystery Snail is one of those rare creatures. Prized by freshwater tank owners for their interesting behavior and intriguing biology, Mystery Snails are an excellent addition to any tank. In this complete care guide, we’ll provide you with all the information you need to make sure your Mystery Snail thrives in your aquarium. So read on to learn more about these fascinating creatures!

Key Takeaways

  • Mystery snails are large freshwater snails that come in an assortment of colors.
  • These snails are very willing to eat detritus and algae but aren’t the best cleaners when it comes to cleaning up fish waste and other debris.
  • Mystery snails can experience poor shell growth and overpopulation when left untreated and unmonitored.

An Overview of Mystery Snails

Scientific NamePomacea spp.
Common NamesMystery snails, Apple snails
FamilyAmpullariidae (sometimes referred to as Pilidae)
OriginSouth America
DietOmnivore
Care LevelEasy
ActivityModerate
Lifespan1 to 3 years
TemperamentPeaceful
Tank LevelBottom
Minimum Tank Size10 gallons
Temperature Range68 to 84° F
Water Hardness12 to 18 KH
pH Range7.0 – 8.4
Filtration/Water FlowLow to High
Water TypeFreshwater
BreedingEgg-layer
Difficulty to BreedEasy
CompatibilityCommunity Tanks
OK, for Planted Tanks?Yes

What Are Mystery Snails?

Depending on who you ask, mystery snails are either the best or worse thing that has ever happened to their freshwater aquarium. These are large and colorful snails that help keep the aquarium glass clean but that can also quickly overpopulate the system if left uncontrolled.

The term mystery snail generally refers to all species in the Pomacea genus under the Ampullariidae family. Depending on the exact species being considered, coloration can vary which leads to more exact common names, like black mystery snail or golden mystery snail. In general, mystery snails are categorized as Pomacea bridgesii, though this may not always be the right taxonomy.

Another common term for the mystery snail is apple snail. This is because all members under the larger category of Ampullariidae are known as apple snails. However, mystery snails are much different from true apple snails.

Mystery Snail Anatomy

Snails are simple creatures. So much so that many hobbyists overlook exactly how their anatomy and physiology benefit their freshwater aquarium. In fact, snails are fascinating creatures that are able to tolerate some of the fastest-changing environments on this planet.

Basic snail anatomy is as follows (picture source from Lander University):

Mystery Snail Anatomy

Shell. All snail shells, including mystery snail shells, are mostly made of hard calcium carbonate that grows with the snail for the duration of its life; this calcium carbonate is very similar to what saltwater corals are made of! At the center of the shell is typically a pointed whorl.

Most of the needed calcium is taken in through diet. A chipping or brittle snail shell can mean a lack of nutrients. Snail shells can come in many colors, though mystery snails usually come in brown, black, and yellow.

Foot. The foot is the long muscular fleshy bottom of the animal. Contractions of these muscles allow the snail to propel itself forward. Snails coat their foot in a unique thin layer of mucus which allows them to stick to many surfaces. Foots can come in different colors as well, though mystery snail feet are typically black, tan, or light yellow.

Operculum. The operculum is a small, usually calcareous, disc that creates a seal with the shell and covers the body of the snail when retracted. Not all snails have an operculum, but mystery snails do. If the operculum of your snail has fallen off, there is a good chance that it is either dead or dying.

Mouth and radula. The mouth is one of the coolest adaptations of freshwater, saltwater, brackish, and terrestrial snails. Most snails use a radula, or a specialized tooth-covered tongue, to scrap off algae and other microflora from hard surfaces. However, some snails, like the marine cone snail (Conus spp.), have evolved a proboscis that fires a venomous harpoon.

The next time you see your mystery snail on the glass, look for its mouth and radula. You will see the radula scraping away any algae that might be present.

Tentacles. Not to be mistaken for antennae, aquatic snails have two tentacles that they use to locate food. These tentacles cannot be withdrawn.

Siphon. One of the few snails to have a siphon, this morphology makes mystery snails unique. A siphon is a long tube–longer than the snail’s tentacles–that can be used to reach above the surface of the water to breathe air. This is an important adaptation to surviving poor water quality, incorrect water parameters, and low levels of dissolved oxygen.

Eyes. Aquatic snails have relatively large eyes that they use to detect light sensitivity. Though this can help locate some food, their eyes are largely used for spotting predators.

Origin and Habitat

Most pest snails originate from Asia, but the mystery snail actually comes from the Amazon River basin throughout South America which is home to many other species of tropical fish and invertebrates. More specifically, mystery snails have been documented in Brazil, Paraguay, Peru, and Bolivia. Due to how prolific these snails are, they have spread as an invasive species to southern regions of North America, from Central America up through Florida, United States.

Mystery snails especially excel in densely vegetated areas where algae is free to grow. One thing to note is that these snails are usually found in harder, cooler waters. This will be important to consider when adding them to your freshwater aquarium.

Appearance

Mystery snails are a favorite snail for hobbyists due to the many colors and patterns they come in. These snail shells basically come in every color, including brown, black, green, yellow, and even blue. The foot of the snail is usually either black or tan depending on the color of the snail shell.

Mystery Snail

These snails have a round appearance with a smooth shell and pointed whorl. On average, they grow to be about 1 to 2 inches. Their tentacles are very noticeable, which can become problematic if kept with fin nippers.

Here are some of the most common varieties of mystery snail to find at local fish stores:

  • Black mystery snail. This snail has a dark brown shell and a near-black foot. The shell sometimes has long black lines with lighter brown ones in between.
  • Golden mystery snail. The golden mystery snail has a deep yellow shell with a light yellow foot. The top of the foot often has speckles of gold flakes. Though these snails might look it, they are not albino.
  • Blue mystery snail. One of the odder colors of snail shell to find, the blue mystery snail has a bluish-ivory shell with a dark, ash-colored foot. The shell may sometimes have streaks or patches of yellow or white.

How Long Do Mystery Snails Live?

Mystery snails don’t live a very long time. On average, most hobbyists find that they live for about 1 to 3 years. Sadly, there is no way to tell how young or old a new snail is, which means that you can potentially have it for a much shorter time than this.

Do Mystery Snails Need New Shells?

No! Mystery snails do not need new shells. All snails grow with their shells and are physically connected. Removing a snail from its shell kills the snail. This is in contrast to hermit crabs which need bigger shells as they grow.

Can You Tell A Male Mystery Snail From A Female?

Mystery snails reproduce sexually and both a male and female are required for spawning. Luckily, there is a way to tell male mystery snails apart from females. Unluckily, females have the ability to hold sperm for several months which means that you may still get baby snails from a newly added mystery snail in your tank even if there are no males present.

Here is how to tell males apart from females:

  1. Carefully remove the snail from the aquarium.
  2. Hold the snail on its back.
  3. Once the snail starts to come out of its shell (while still being held on its back), look at the space in between the head and the shell.
  4. Females will have an open space while males will have a noticeable light-colored penis sheath.
  5. Place the snail back in the water.

Mystery Snail Care

Mystery snail care is very easy and requires little aquarium experience. That being said, these snails still require a fully cycled aquarium where toxic ammonia can be safely converted into nitrate without having to worry that you’ll kill your fish and invertebrates.

Are Mystery Snails Hard To Keep Alive?

Mystery snails are not hard to keep alive. Keep in mind that they don’t have a very long lifespan, so an early death may not be your fault. If you do find that other species of snail or invertebrate are also dying along with your mystery snails, then there may be a problem with water parameters. However, mystery snails generally require little to no additional tank maintenance.

Aquarium Setup

Mystery snails aren’t picky about their surroundings. These freshwater snails can be kept in a simple start-up aquarium or a mature planted display.

A mystery snail tank does not need to be set up with them in mind, though providing some snail-specific hiding spots will be appreciated. This can be in the form of live or fake plants, rocks, driftwood, and other fish-safe decorations.

These snails are so hardy that they don’t even need an aquarium filter as long as water quality is maintained!

Tank Size

The minimum tank size recommended for mystery snails is 10 gallons; 10 gallons will allow for about 2 or 3 of these snails. These are some of the larger freshwater snails available and they create a lot of waste, so it’s better to have a bigger tank that not only provides more surface area for grazing but also dilutes wastes with more water volume.

That being said, many hobbyists are able to set up a 5 gallon mystery snail tank without any problems. This is completely possible as long as water quality is maintained and food is supplemented when the naturally occurring algae runs out. Also, keep in mind that a smaller tank limits how many other tank mates can be added as mystery snails create significant waste.

Water Parameters

Like other invertebrates, mystery snails are sensitive to ammonia and nitrite. They are more tolerant to nitrate but will suffer from excessive levels, usually over 20 ppm. They are also intolerant of copper, which must be considered if dosing medications into the display aquarium.

Mystery snails are very forgiving of imperfect water parameters, but they do have some preferred conditions. Most notably, these snails do best in a cooler water temperature between 68 to 84° F. Many of the snails available in the aquarium hobby are kept at regular tropical temperatures in the upper 70s, though some hobbyists have better success in the lower range.

Similarly, mystery snails refer harder and more basic water with a hardness level between 12 to 18 KH and a pH level between 7.0 to 8.4. This is different from other Amazonian species that come from their natural habitat, which oftentimes prefer softer, more acidic water parameters. That being said, most snails are kept in standard tropical conditions in pet stores.

Filtration and Aeration

Believe it or not, mystery snails need decent filtration. These snails are constantly grazing and what goes in must come out. Mystery snails can be kept in an aquarium filtered by hang on the back filters, canister filters, or sponge filters.

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Some hobbyists add this species to their Walstad aquariums which rely on a delicate balance between fish waste and plant intake to stabilize water parameters without additional filtration. In our opinion, there are better snail options for these types of aquariums, like nerite snails (Neritina spp.), which are excellent algae cleaners and can’t reproduce without brackish water conditions.

There is some benefit to snail poop, though. Interestingly, mystery snail feces get caught in the trailing mucus of the snail. Over a short period of time, this cultivates infusoria, a combination of microscopic organisms, which are appreciated by small invertebrates and fry. For this reason, mystery snails are often added to breeding tanks to help keep small fish fed.

Otherwise, mystery snails don’t necessarily need additional aeration as long as dissolved oxygen levels are maintained. These snails do have a ton of personality though, and it’s not uncommon to find your mystery snail floating to the bottom of the tank past a column of bubbles.

Lighting

Mystery snails can tolerate most lighting conditions. Like other freshwater fish and invertebrates, they appreciate having areas of shade to hide and forage when need be.

On top of this, most species of snail are nocturnal and the mystery snail is no different. Though these snails are semi-active during the day, they are typically most active at night; it should be noted that snails have very irregular sleep patterns and have been known to stay inactive for several days on end. While this is normal, it is best to keep an eye on the following behaviors of your mystery snail as well as those of other tank inhabitants.

Aquatic Plants and Decorations

Mystery snails absolutely love live plants and decorations. These snails spend the majority of their time scraping algae and other biofilms off of surfaces throughout the fish tank, and the more surfaces available the better.

One common fear of keeping freshwater snails is that they eat healthy live plants. Mystery snails are very unlikely to eat healthy plants, though they will help clean up decaying leaves and stems. It should also be noted that some hobbyists have found their mystery snail-eating duckweed (Lemnoideae subfamily) at the top of their tank. This is usually welcomed as duckweed can be overly prolific.

That being said, mystery snails do not need live aquatic plants to thrive. As long as the tank has a mature layer of algae and biofilm, these snails can be sustained with some added algae wafers and vegetables.

Tank Maintenance

In some ways, the less maintenance the better for a mystery snail colony. These snails like ‘dirty’ conditions–or rather, areas with plenty of natural food that keeps them busy. Because of this, the front of the aquarium glass usually stays pretty clean.

However, snail poop can definitely accumulate on the bottom of the aquarium, which can become unsightly and lead to some water parameter issues over time; the mystery snail is one of the messier types of snail to keep, so water quality needs to be maintained. To help prevent poor water quality, occasionally vacuum the bottom of the substrate with an aquarium siphon. This can be done during 15-25% weekly or biweekly water changes.

Filter media should also be changed as needed. Sponge filters can be rinsed out less often than usual as snails love to graze on what’s available.

Substrate

Mystery snails can be kept on gravel, sand, or a bare bottom. These snails travel easier over smooth surfaces but will appreciate eating detritus that gets caught between coarse gravel. On the other hand, sand is much easier to siphon to remove snail waste.

Community Tank Mates

This species of snail is the perfect community tank mate. They leave fish and other invertebrates alone while helping keep the fish tank clean. However, some community tank species might have a special appetite for your mystery snail.

In general, known fin nippers should be avoided. Mystery snails have especially long tentacles that could look appetizing to a curious fish. Fin nippers might include larger barbs and some larger tetras. If you have healthy mystery snails, they should be able to retract before any damage can be done.

Known snail-eaters should also be avoided. This largely includes loaches and puffers.

Mystery snails are a popular combination in a betta fish tank. For the most part, this depends on the temperament of the betta fish. Some bettas are more aggressive than others and might try to nip at the snail.

Can You Keep Only 1 Mystery Snail?

Yes! You can only keep 1 mystery snail per tank as they are not social animals. This is especially useful for small tanks, like a betta fish setup.

It is also strongly recommended to only keep 1 mystery snail when breeding is not desired. As we’ll see, these snails will breed when given the opportunity, and having multiple in a tank can quickly lead to overpopulation. Unfortunately, female snails can withhold sperm for several months, which means that you can still end up with an overpopulation.

How Many Mystery Snails Should Be Kept Together?

The general rule of thumb is 1 to 2 mystery snails per every 5 gallons of water. How many snails you can have largely depends on the amount of mechanical and biological filtration available in the aquarium. Once these snails start to breed, it can become near impossible to keep track of how many are actually in the system.

Mystery Snail Food and Diet

Mystery snails are pickier eaters than you might think. They don’t eat live plants and they won’t clean up fish waste. In fact, these snails love a healthy diet of leafy greens and algae wafers.

That isn’t to say that you need to spend a ton on feeding mystery snails. They will largely accept leftover fish flakes and other live, frozen, and freeze-dried foods that make their way to the bottom of the tank. They will also appreciate the occasional algae wafer or pellet and blanched vegetable from time to time. In fact, blanched vegetables can be used to capture and remove overpopulations of snails.

If you notice that your snail has a broken or chipped shell, it may be lacking calcium in its diet. A higher-quality food can be supplemented, or a snail-specific calcium block can also be given.

As mentioned before, mystery snails have been known to eat duckweed, though this isn’t their typical diet.

Breeding Mystery Snails

Breeding mystery snails is very, very easy and often happens on its own. If you have a male and female mystery snail in your tank, they will breed as long as their basic needs are met. As mentioned before, some females can even hold sperm for up to a year, which means that you can end up with baby snails long after introducing a solitary snail into the system (video source).

If you find that your mystery snails aren’t breeding, try performing larger water changes and feeding better quality food more often. Be warned that once they start, they won’t stop!

Luckily, snail eggs can be crushed if found. These eggs are usually laid in a clutch right above or below the water line.

Common Snail Problems

Though snails are some of the easiest freshwater creatures to keep, there are some problems you can potentially run into.

Brittle or Irregular Shell Growth

Shell health is important! For the most part, good water quality will allow for healthy shell growth, but sometimes nutrients are lacking. The main nutrient that snails need for a healthy shell is calcium.

If you notice chipped or cracked shells, usually indicated by a white scratch or indent, then your snail might be struggling with generating a healthy shell. Snails are attached to their shells and need nutrients to maintain them. Calcium can be supplemented through a higher-quality diet or through snail-specific calcium blocks.

Overpopulation

The second most common problem snail enthusiasts run into is overpopulation. Mystery snails readily breed and can quickly overtake a freshwater tank when parameters are met.

Overpopulation can be difficult to deal with as hobbyists need to find a place for excess snails. Most hobbyists move these snails into a separate low-maintenance tank, where they let the colony live among an abundance of live plants. Other hobbyists give their snails back to their local pet store or to other hobbyists with a predatory tank that feeds snails.

Unfortunately, many hobbyists need to remove snails once they become a problem and humanely dispose of them. If you happen to find snail eggs before they hatch, then they can be crushed.

Final Thoughts

Mystery snails are easy to keep, easy to find, and easy to add to the freshwater community aquarium. These snails grow larger than most other freshwater species and can create an above-average amount of waste, but they are efficient algae cleaners that keep aquarium glass clean. Poor shell health and overpopulation can become problems if left untreated.

by Mark

Mark is the founder of Aquarium Store Depot. He started in the aquarium hobby at the age of 11 and along the way worked at local fish stores. He has kept freshwater tanks, ponds, and reef tanks for over 25 years. His site was created to share his knowledge and unique teaching style on a larger scale. He has worked on making aquarium and pond keeping approachable. Mark has been featured in two books about aquarium keeping - both best sellers on Amazon. Each year, he continues to help his readers and clients with knowledge, professional builds, and troubleshooting.

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