Various freshwater snails

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As apple snails are only a small part of the snail species that inhabit aquaria and ponds around the world, thus some basic information on other common freshwater snails cannot be left away.
This overview is by no means complete and it is therefore advised to take a look at other websites as well to gather more specific information (see link section) as well. Remarks, suggestions or questions about this section (or other sections) can be send to the author by using the question form.

Here is a small guide to facilitate to determination of your aquarium freshwater snails.
Please bear in mind that this guide is by no means complete. It's only intended to give a rough overview to help you in the right direction. For more specific information, you should use more specialized literature.

  

 

Determination guide
for common freshwater snails


Cup-shaped shell without whorls:
limpet

 

 

Drop-shaped shell:

neritina

 

  • Heavy, drop-shaped shell, often with colourful pattern. Small, non-concentric operculum (shell door grows at the side of the columella, not at all sides) --> Neritidae

 

Discoidal shell (flat, all whorls in one plane):

ramshorn

 

  • Operculum present, shell size often over 3cm, often with longitudinal stripes (following the whorls - spiral bands) --> Marisa (Ampullariidae)
  • No operculum, shell size less then 3cm, no stripes and/or colour patterns. --> Planorbidae

 

 

Globose shell:

mystery snail

 

  • Globose shell, often with spiral banding pattern. Size: up to 5cm. Concentric operculum --> Viviparidae

 

Conical shell:

Physidae

 

  • Thin to medium thick shell. Relatively small (2cm max) snails. Sinistral (left-turned) shell. Large shell opening (aperture) and no operculum. --> Physidae

 

trapdoor snail

 

  • Heavy shell with sharp, pointed top (sometimes absent due to errosion). Size up to 3 cm max. Rough shell surface. Concentric operculum. --> Thiaridae
pond snail

 

  • Thin shell, large shell opening. No colour patterns. Sharp shell top and no operculum. Size up to 7cm max. Snail needs to surface once in a while to refresh air in lung. --> Lymnaeidae


 

  
shadow

 

 

Subclass Pulmonata

Family Acroloxidae

The snails from this family don't have a classic, spiral shell, but a hood-shaped shell.
The Acroloxidae family consists of 2 genera: the genus Acroluxus with 5 species (North America, Europe and northern East Asia) and the genus Pseudancylastrum with 3 species (all endemic to Lake Baikal).
The size of these snails varies from 2 mm to 8 mm. The snails present themselves as small white spots on the plants and the glass. They are not considered to be harmful, although large numbers of these can be annoying when they cover whole parts of the glass. However, as with all snails, if the availability of food is reduced, the population of these snails will decrease as well.

Acroloxus lacustris
Acroloxus lacustris, light from underside.
Acroloxus lacustris
Acroloxus lacustris
, sideview.
Acroloxus lacustris
Acroloxus lacustris
, reflecting light source.

 

Family Lymnaeidae

The nomenclature of the Lymnaeidae is still somewhat unclear. The family is divided in two generally accepted subfamilies: Lancinea en Lymnaeinae.
The Lancinea subfamily is abundant in western North America (Columbia, Umpaqua, Klamath and Sacramento River drainage) and consists of the genera Fisherola with one species and Lanx with four species in two subgenera.
There is much disagreement about the nomenclature of the cosmopolitan Lymnaeinae subfamily. Some authors only accept one genus (Lymnea), while others prefer to up to 7 different genera (Galba, Stagnicola, Radix, Lymnea s.s. and other genera).

Respiration in these snails is aerial, through lungs. Their preferred habitats are stagnant to slow streaming waters with heavy vegetation.
Both the shell as well the body of the snail are dextral, which means that the shell opening is situated at the right if one looks at the shell with the top pointed upwards and the shell opening visible. The lung opening at the right side of the body indicates the dextral body structure.
The transparant eggs are deposited in a firm, gelatinous clutch on plants, stones or other objects. These snails are hermaphroditic and two snails are enough to get large numbers of them in relatively short time.
The size of these snails varies from 1 cm (Lymnea truncata, Müller), 3 cm (Lymnea peregra, Müller) to 7 cm (Lymnea stagnata, Linnaeus).

Lymnea ovata
Mating Lymnea (radix) ovata snails. (picture not licenced under creative commons)
Lymnea auricularia
Lymnea (radix) auricularia. (picture not licenced under creative commons)
Lymnea stagnalis
Lymnea stagnalis, eggs.
Lymnea stagnalis
Lymnea stagnalis (giant pond snail).
Lymnea stagnalis
Lymnea stagnalis, size: 3.5 to 7.0 cm.
 

 

Family Physidae

The Physidae family is native to Europe, North Asia, North and Middle America and western Africa.
Four genera are generally accepted: Physa, Physella, Aplexa (Europe, America, Asia and Africa) and Stenophysa (Central America).

The snails from this family have a sinistral shell (left turned) and body (lung opening at the left) and a mantle skirt with two lobes embracing the shell at the left and at the right side of the body. This mantle extension enlarges the body surface; probably to enhance the exchange of O2 and CO2 (sort of a gill function), which enables these pulmonates to stay submerged for longer periods.
These snails lay transparant eggs that are embedded in a firm, gelatinous clutch on plants, stones or other objects.
The size of snail in the Physa genus varies from 13 mm (Physa fontinalis) to 20 mm (Physa acuta).

Physa acuta
Physa acuta, size: 12 mm.
Physa acuta
Physa acuta with the left mantle lobe visible.
Physa acuta
Physa acuta with the right mantle lobe visible.
Physa acuta
Physa spec. woth beautiful mantle pigmentation, visible through the fragile shell. (picture not licenced under creative commons)

 

Family Planorbidae

Panorbis sp.
Planorbis species (Ramshorn snail). (picture not licenced under creative commons)
Panorbis sp.
Planorbis spec. (Ramshorn snail). (picture not licenced under creative commons)

The Planorbidae are by far the largest family of aquatic pulmonates that are widely distributed over the world.
Three subfamilies are recognised in the Planorbidae: Rhodacmeinae, Buliniae and Planorbinae, the latter two are subdivided in tribes, each consisting of several genera. However, there is much discussion about many of the genera and the species. Many genera and species are considered to be invalid and synonyms of each other by several authors.

The subfamily Rhodacmeina contains one genus with three species that all live in the Tombigbee (Alabama) and Tennessee river drainage in the southeastern U.S.A.

The widely distributed subfamily Buliniae consists of three tribes:
- Bulinini with four genera: Bulinus (Africa, Madagascar, western Asia and southern Europe), Indoplanorbis (southern Asia), Laevapex (eastern North America) and Gundlachia (South and Middle America).
- Physastrini with possibly 12 valid genera: Glyptophysa (south-eastern Australia, Tasmania, New Zealand and New Caledonia), Physastra (Australia, New Zealand, New Caledonia, Sumatra, Philippines and several Pacific islands), Ameriana (north and north-east Australia, New Guinea, Indonesia, Thailand and the Philippines), Barnupia (tropical Africa), Ferresia (North America), Pettancyclus (Australia, New Zealand, East and southern Asia and eastern Africa), Isidorella (western and southern Australia), Bayardella (Australia), Patelloplanorbis (New Guinea), Oppletora (north Australia), Ancylastrum (Tasmania) and Miratesta (Indonesia).
- Camproceratini with two genera: Helisoma in North America and Planorbarius (North America, Europe and northern Asia).

The subfamily Planorbinae consists of five tribes:
- Planorbulini with 1 genus: Planorbula (North America). However, according some authors, this tribe also includes the genera Menetis, Promenetus and Planorbella.
- Biomphalariini with 2 genera: Biomphalaria (Africa, Madagascar, South and Middle America, Western Asia and Europe) and Drepanotrema (South and Middle America).
- Planorbini with 7 genera: Planorbis (Europe and western Siberia), Afrogyrus (tropical Africa and Madagascar), Afrogyrorbis (tropical Africa), Anisus (Europe and western Siberia), Bathyomphalus (Europe and Northern Asia), Gyraulus (Europe, Northern and East Asia, Africa and Australia) and Choanomphalus (western Siberia rivers, Volga local population in Lakes).
- Segmentini with 6 genera: Segmentina (Europe and northern Asia), Hippeutis (Europe and northern Asia), Lentorbis (tropical Africa), Polypylis (East Asia) and Helicorbis (East Asia).
- Ancylini with one genus: Ancylus (North America, Northern Europe and Northern Asia).

Most Planorbidae have a flat shell, somewhat similar to a ramshorn in shape, hence their common name ramhorn snails.  However, not all snail with this shape are Planorbidae, for example the Ampullariidae genus Marisa has a similar shell shape.
The shell of many Planorbidae is right turned (dextral), but their body is sinistral, a situation similar with the Lanistes genus of the Ampullariidae (apple snails), which have a sinistral shell and dextral body. Because collected shells are often empty, these snails are considered dextral for practical, determination reasons, but on anatomical grounds one could call these snail hyperstrophic dextral. On the other hand, some Planorbidae genera like Ameriana and Physastra from the Physastrini tribe have sinistral, globose conic shells, while the Ancylus genus have flat hood-shaped shells, similar to the Acroloxidae snails.

The eggs of these hermaphroditic Planorbidae snails are laid in transparant clutches on plants, stones or other objects.
Most Planorbidae members prefer habitats with slow moving or stagnant waters like ponds, lakes and swamps.

 

Subclass Prosobranchia

Family Thiaridae

The species Melanoides tuberculata (Müller, 1774) and Melanoides granifera (Lamarck, 1822) are the best know species of this family and occur in almost all aquaria around the world.
The Thiaridae are cosmopolitan freshwater snails. Most species of this family crawl through the mud in search for food, a life style that makes them attractive to keep in aquaria as they loosen the soil. It also makes these snails quite conspicuous and the best changes to see them are during the night and when overcrowding has occurred. In the latter case, overfeeding of the fish in the aquarium might have caused an excessive population growth of snails.
Their toughness is probably the principal reason of their success both in the wild as in the aquaria world. The horny operculum of these snails enables them to close their shell to protect them against drought and predators. They can easily survive periods of drought for months, hidden in the bottom.
Another thing that contributes to their ability to survive is the strength and thickness of their shell; most snail eating fish, as well as many other predators are not able to crush their shell. Even predators that swallow them whole won't always benefit from their meal as these snails can sometimes survive a trip through the intestines. This is a great advantage for these snails as they can spread to new areas after being eaten by a bird and expelled with the faeces.
One of the most remarkable features of these snails is their parthogenetic reproduction: unfertilised females are able to reproduce. So only one snail is needed to have more in short time.

Melanoides granifera
Melanoides granifera
.
Melanoides granifera
Melanoides granifera
.
Melanoides tuberculata
Melanoides tuberculata
.

Genera:
- Aylacostoma: Central and South America
- Cubaedomus: Cuba
- Dorissa: South America
- Fijidoma: Fiji Islands
- Hemisinus: South America
- Melanatria: Madagascar
- Melanoides: Southern Europe, Africa Terebia; south Asia, Oceania
- Pseudopotamis: Australia
- Sermyla: southeast Asia, Oceania
- Sermylasma: Australia
- Thiara: East Africa to Polynesia, some species also very wide ranging
- Tylomelania: Celebes

 

Family Viviparidae

Viviparus viviparus
Viviparus viviparus
(Linnaeus).

Viviparidae have a worldwide distribution.

Subfamily Viviparinae:
- Viviparus: Eastern North America and most of Europe.
- Tulatoma: endemic in Coosa River, Alabama, USA.

Campelominae or Lioplacinae:
- Campeloma: Eastern North America.
- Lioplax; Eastern North America.

Bellamyinae:
- Bellamyia: Africa, India, southeast Asia.
- Cipangopaludina: east and southeast Asia, and as an exotic elsewhere.
- Notopala: eastern Australia. Larina; northeast Australia.

 

 

Family Neritidae

Neritina natalensis
Neritina natalensis
(Reeve, 1845), a South-African freshwater species.
ancylus sp.
Septaria species (Freshwater limpet).
Neritina natalensis
Unknown freshwater nerite.
Possible origin: Pangandaran, Java?
Neritina natalensis
Unknown freshwater nerite.

Most members of the Neritidae family are salt-water snails, but some species have adapted to brackish and even freshwater environments.
The drop-like shape of their shell makes it easy to distinct these snails from most other freshwater snails. The often beautiful and attractive colour pattern of their shell is differs from the generally conspicuous appearance of most other freshwater snails.
The Neritidae have separated sexes and the small white eggs are deposited on rocks, the glass and other solid objects. The growth of these snails is fairly slow, which explains why these snails are often more expensive the fast growing snails like apple snails.
For the aquarist these snails are an attractive choice, both by their look as for algae control. They have not much appetite for plants, whilst algae aren't safe for them.
Despite these snails are not always easy obtain, several species are occasionally offered in the aquarium trade.

- Clypeolum: widespread in the tropical Pacific basin.
- Fluvionerita: mountain brooks of Jamaica.
- Neritilia: all tropical regions.
- Neritina: tropical Atlantic coasts, Indo-Pacific.
- Neritodryas: Malay archipelago.
- Septaria: rivers and streams of large South-Pacific islands, Madagascar, India.
- Theodoxus: Europe and southwestern Asia.

However, there is no complete agreement between the different authors regarding the genera and ranges given for their included species.

 

More info?

Take a look at these sites:

- for good info about species, genera etc. With lots of photographs.
- Contains well observed and descibed info of snail behaviour in Physidae snails.
- Not only Ampullariidae snail are listed here, also a valuable collection of all kinds of freshwater snail info can be found here. One of the better websites on snails around....
- . The Resource Site for Students, Educators, and anyone wanting to learn more about the fascinating world of, the Molluscs.

 

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