Last Updated: 4/12/12
My Trapdoor Snails
Photos of My Trapdoor Snails
Photos of Other People's Trapdoor Snails
Survive in aquariums: Yes
Survive in warm ponds: Yes
Survive in cold ponds: Yes
Plant eating capacity: Low
Algae eating capacity: Moderate to High
Breeding: Sexual, live-bearing
The black Japanese trapdoor snail's Latin name is Viviparis malleatus; viviparis means they give live birth. This is the only snail's scientific name about which I am 100% sure! Trapdoors are large (1-2 inch, normally about 1.25") snails shaped like a swirly ball. They eat algae and plants. Many consider them the ideal snail for ponds since they reproduce slowly, do little harm to plants, and can survive water temperatures down to right above freezing. While trapdoor snails do not require dirt in the bottom of the pond to overwinter, they enjoy having a few stray leaves or a pot of dirt topped with pea gravel to "drive around in." They do better in older ponds with more food.
Trapdoors are non-hermaphroditic, live-bearers and thus breed more slowly than other snails. That means that each trapdoor snail is either a male or a female. Females give birth to from about 6 to 20 babies at a time.
Mary Jo reported the following on 5/8/03: "...Twice I witnessed a trapdoor give birth. Once, two babies were expelled, like pearls in membranes, and momma held the baby with her tentacles & removed the membrane, then released the baby. The second time, three were born. Both occasions were in August. And yes, trapdoors are escargo to raccoons. They will ignore the fast-moving fish & eat every trapdoor they can find...."
Later, Mary Jo said on 5/8/03 that you can sex trapdoor snails by the antennae. She said she read males have short antennae that point to the right while females have longer ones pointing towards the vent. She said, "This makes sense considering that she uses her antennae to intercept the newly emerged baby & hold it while removing the birth membrane." I have not examined trapdoors that close to say whether this works or not.
Other sources say that the females have straight tentacles while the right tentacle of the male is short and curved. He uses that to transfer sperm to the female. Check out this link for more information about sexing trapdoor snails and photos.
I have been adding trapdoor snails to my 1800 gallon pond almost yearly from 1997 to 2011. In my pond, most died for no reason. I have added dozens but rarely see them. I saw a live one moving around on 9/27/98 (and have seen them often since)! I think raccoons ate a lot of mine. Sometimes I saw many in a week and, other times, I did not see any for months. Of course, I was not looking that hard! I found them most often when netting the bottom of my larger pond to remove pea gravel the koi moved there. A number of times I almost failed to notice a snail with the gravel and saved it just in time. I usually add a dozen trapdoors yearly. By the next year, most are gone. I think the raccoon hunts them down. I believe the raccoons and maybe the herons just keep eating them so it does not make sense to keep adding them. I did not add any in 2012.
Photos are listed from oldest to newest.
An empty trapdoor snail shell removed from my 1800 gallon pond on 2/13/05.
Japanese trapdoor snail that I got on
Japanese trapdoor snails that I got on 5/23/07.
I got a dozen adult trapdoor snails on 4/7/10. One female had given birth to 13 babies in transit
which is common.
Adult trapdoor snails and babies
8 adult trapdoor snails
Snails - trapdoor snails (the biggest ones) and their babies (the smallest ones), black ramshorn snails (the round ones), and Melantho snails (the elongate ones), on the day that I got them, 4/28/11.
Photos are listed from oldest to newest.
Daxe sent a photo of a trapdoor snail next to her newly-born babies in an aquarium on 8/2/04. The snail had recently been in a pond, hence all the algae growing on her.
Nora sent me these sequential photos of a trapdoor giving birth on 11/7/05. There are other
snails around. It is the one on the left from whence a baby comes. The photos were sent to me
Karen sent me this photo of a trapdoor snail on 4/14/07.
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