Answer, unless you have a Japanese trapdoor snail, It's not!
The Apple Family
In the aquarium trade the "Ampullariidae" or apple snail family, more specifically Pomacea, has been the source of some confusion in past years in relation to species name, because of this many of the subspecies have been given the wrong name time and time again.
At the center of the confusion is the commonly and incorrectly known "Mystery Snail" (referring to spike topped apple snail for those who know the correct name). They were originally classed Pomacea bridgesii and thought to be the same as Pomacea canaliculata (channeled apple snail a close cousin that can survive lower temperatures and eat live plants and almost anything that will fit in their mouth). they were then thought to be another form of bridgesii “Pomacea bridgesii diffusa” then later in 2003 they were correctly reclassified as Pomacea diffusa, a distinct species, using genetic analysis [Cowie and Thiengo 2003]. Pomacea brisgesii is a large wild form that is quite rare.
Mystery or Not?
"Mystery Snail" is an incorrect name which originates from early in the aquarium trade when Japanese trap door snails (true Mystery Snails) were popular and commonly sold in fish stores. This species of snail (Japanese trap door) gets the name "Mystery" because they give birth to live young, making it a mystery to people early in the hobby where the babies were coming from when there was no eggs. 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 or B. they genuinely didn't know what they were, making them a mystery snail and the name stuck.
Cousins
As well as P.diffusa aka spike topped apple, the ampullaridae or "apple" 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 these eat live plants (and anything they can fit in their mouth). They can also 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 and are not allowed to import any 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 dyeing plants unless provided no other food. There are many colours 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, unlike P. canaliculata, also has freckles on their foot. A black foot often has orange/red spots and a white foot often has pale yellow spots. They 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. There is also another defining difference that the P.canaliculata is named for, this is the 45DEG channel between shell whorls giving it the name “Channeled apple snail” it is also much larger, growing to about the size of an apple.
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 be likely be in extremely rare cases, If you have a single snail lay eggs it is more likely 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 function is likely the reason people assume the 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.
If you found this article because you were looking to correctly ID your apple snail hopefully this helped, for more info contact Mellow Snello on Facebook or join the group "Aquatic Snails NZ" (if outside NZ join “Aquatic Snails” its a good group but here in New Zealand we cant get a lot of the species/colors in this group). You can also check out Mellow Snello Aquatics | Hamilton (wixsite.com) for care sheets and info on snail varieties available in NZ.
If you live in NZ and have an aquatic snail not listed on the website Mellow Snello Aquatics linked above please let us know through the website contact page on in the NZ group. (We are currently working on a list of coldwater snails including lymnaea)
More info: popcultchur.wixsite.com
*Left - Pomacea canaliculata. *Right - Pomacea diffusa
