Apple Snail Taxonomy, It’s A Mystery! … Or Is It?

When trying to figure out what type of aquatic snail you have, there can often be a lot of confusion. Names like “Mystery” and “Apple” are thrown around, but did the person you purchased them from really know what they were selling you? After a bit of research and joining several snail groups I found a lot of people were just as confused as I was, so I started delving deeper into the world of aquatic snail taxonomy and here is what I have learned to better understand exactly what is in my aquarium.

The Apple Family

In the aquarium trade the Ampullariidae or apple snail family, more specifically Pomacea, has been the source of debate in past years in relation to species name. Because of this many subspecies have been sold with the wrong name so many times it stuck.

At the center of the confusion is the commonly and incorrectly known “Mystery Snail”, in saying this, there are aquarists that have kept up with the nomenclature and will correctly identify them as a variety of apple snail. They were originally classified as Pomacea bridgesii and often thought to be the same species as Pomacea canaliculata, another member of the Ampullariidae family.

Later they were thought to be another form of bridgesii, Pomacea bridgesii diffusa, then in 2003 were correctly reclassified as Pomacea diffusa, a distinct species, using genetic analysis [Cowie and Thiengo 2003]. The actual Pomacea bridgesii being a large wild form that is quite rare.

Where does the name Mystery come from?

“Mystery Snail” originates from early in the aquarium trade when Japanese trap door snails (true mystery snails) were popular and commonly sold in fish stores. They were given the name Mystery because they gave birth to live young and to people early in the hobby it was a mystery where the babies were coming from when there were no eggs present.

When P.diffusa was introduced into the aquarium trade they were either called “mystery” because; A. the owner believed they were just a different type of trap door snail like the ones they had previously sold, or B. they didn’t know what species they were, making them a mystery snail and the name stuck.

As well as P.diffusa aka spike topped apple, the ampullaridae family includes P.canaliculata aka Channeled Apple, P.maculata aka Island Apple and more, however these 3 are the more common varieties people are likely to own as pets.

Depending on where you live, these snails may have strict laws prohibiting owning, breeding or selling but this is more often the case for the P.canaliculata and P.maculata as they eat live plants and almost anything else they can fit in their mouth, because of this they can become extremely invasive if released into the wild. For example in New Zealand we are only allowed P.diffusa and P.canaliculata from the Ampullaridae family as pets and we are not allowed to import either of them.

P.diffusa’s lifespan can range from 1 to 4 years depending on water parameters and care level and will only eat dead or dying plants unless provided no other food, sometimes not even then. There are many colour morphs available depending on the country you live in, the most common being brown and blue (the only colors available in NZ) however other colours include purple, chestnut, ivory, magenta, gold and jade. They can either have a light or dark foot and shell colors include yellow, white, brown and purple. The combination of foot and shell color will determine what colour morph you have.

P.diffusa have freckles on their foot, only grow to around the size of a golf ball and do not have a channel between the whorls of their shell unlike the P.canaliculata, which always has a pale white/yellow to dark brownish/yellow shell and a white foot with no freckles. P.canaliculata is also much larger, growing to about the size of an apple and has a channel between the shell whorls.

It is believed by some people that apple snails are capable of self fertilisation but this has not been observed at a scientific level and if true, would likely be in extremely rare cases. If you have had a single snail lay eggs in your aquarium, it is more likely that you were sold a mated female or even the just the wrong sex, as unmated females can still lay infertile eggs. Adult females can also store sperm and produce babies up to a year after mating, this is likely the reason people assume they are self fertile or able to change sex.

They require space above the water line to lay eggs because if submerged the eggs will drown and they will only lay a clutch if the water conditions meet their requirements. Extra calcium may be required for shell growth and egg production depending on the mineral content of your water and the amount of snails in your aquarium.

For more info or help identifying your snail send clear pictures of your snail to Mellow Snello on Instagram or join the group “Aquatic Snails NZ” (if you're outside NZ there are several international groups where you will be able to find out what varieties are available in your country). You can also check out Mellow Snello’s website for care sheets and info on exotic snail varieties available in NZ.

https://popcultchur.wixsite.com/mellowsnello

If you live in NZ and have an aquatic snail not listed on the website Mellow Snello Aquatics, please let us know through the website contact page or in the NZ aquatic snail group. (We are currently working on a list of cold water snails including Lymnaea)