General description:

The individual species differ a lot regarding their shell shapes and structures. They can be long, conical with strongly pronounced axial or spiralling ridges, but we can also find small, smooth shells of an ovoid shape.

The genus Tylomelania features shell sizes between 10 and 117 mm, whose apices are mostly corroded. All of them have an operculum with a central nucleus and 5 to 11 rings (paucispiral operculum).

The bodies and feet of these water snails are richly colored and high in contrast.

 Ranging from single-colored snails in orange, creme, white and black over specimens with black, orange, yellow and grey tiger stripes to black ones with white dots or dark brown ones with orange tentacles just about anything can be found.

The tentacles are straight, the black eyes located at their bases. The mouth part is clearly set off and seems to be very long and soft – rather "cuddly" ;o)

Range and Habitat:

Sulawesi

There are different climatic zones on Sulawesi due to this island's uncommon form.

The mountain ranges are largely covered by tropical forests. The temperatures in the lowlands and at the coast are between 28 and 32 °C all year round, during the rainy season they are approximately 2 degrees lower.

Tylomelania can be found in the Malili lakes and Lake Poso as well as the respective feeder rivers, on hard or soft substrate, depending on the species.

The largest population density was found at depths between 1 and 2 meters, under 20 meters it decreases significantly. The lakes have a temperature of 27 °C even at a depth of 20 m.

The species portrayed on this site as follows originate from Lake Poso ( 500 m above sea level) and the Malili lakes, or rather and more specifically, Lake Matano (400 m above sea level). These lakes are located in central Sulawesi. Lake Matano is a softwater lake whose maximum pH value is 8.5 according to recent measurements.

The maximum pH value so far measured in Lake Poso is 8. Unfortunately I do not have any data regarding its water hardness.

Parameters from the habitats:

Lake Matano, measured on the northern and the southern shore in May 2008

Temperature    29.5
Electrical conductance value 191 - 227
PH           8.6
gH           7
kH           5
NH4        0
NH3        0
NO2        0
NO3        0
PO4        1,0
FE           0
CU           0

Lake Towuti, measured in the north

Temperature of 32°C shortly under the surface, 29 °C at a depth of 3 m.

Electrical conductance value 181
PH           8.3
gH             6
kH           5 - 6
NH4          0
NH3          0
NO2        0
NO3        0
PO4        2.0
FE           0
CU           0

My special thanks to C. Logemann , for giving me the water parameters. THX a lot.

 Reproduction:

As front-gilled snails they are dioecious, there are males and females. It has not been proved yet but it is highly probable that the male fecundates the female by passing a spermatophor.

The young snails develop in the breeding sac of the female until they hatch. In the fan-shaped sac they are covered in a nutritional substance, which suggests that they are ovoviviparous.

The embryos are – depending on the species – between 2.8 and 17.5 mm in size.

There is a groove starting on the right side of the body running along the foot whose function has not been cleared up entirely yet. It probably serves reproductional purposes, running along the foot and ending on the head in a mantle fold behind the tentacles.

Mura from water-box.de was able to watch a snail giving birth.

The mother snail turns to the side so the groove's mouth lies sideways.                  After a short time a soft white egg appears under the opening where the (reproductional/birthing) groove ends. The egg is transported along the groove, presumably with the help of contractional waves, down towards the snail's foot.

This process took about 5 minutes. Once there the white mass started to dissolve, a totally developed young snail appears and starts crawling, looking for food. A singular observance.

Food:

In the stomachs of snails taken from the wild, sand and diatoms were found.

In the aquarium they like to dig through the muck and accept powdered food of all kinds.

Some species eat cucumbers and bell peppers. I have been able to watch two species actively eating mosquito larvae and carrion.

Behavior in the aquarium:

Some species do not only show irritated reactions to light but also to mechanical disturbances by shrimp.

During the first days the Tylomelanias seem to search for contact and press their heads together firmly several times a day.

After the first few weeks this strong urge for bodily contact seems to wane as soon as they have explored and accepted their new surroundings.

Every species has their little typical characteristics, which are dealt with in the respective species descriptions.

None of the snails digs itself in the ground.

The aquarium:

As all of these snails are taken from the wild at the moment, they show discomfort at too much light even after being diligently adapted to the aquarium. They should find opportunities to retreat, so-called dark corners, in the tank.

The soft water's temperature should be between 27 and 29 °C, an aquarium under 60 cm is not adecuate for them.

 The Tylomelanias start exploring their new surroundings rather quickly.

In a nutshell, we could say that they can be kept very successfully in soft water with KH 2, GH 0 and a pH value between 7,5 and 8,6.

 Several attempts to harden up the water have shown that they also do well in medium-hard water, however, they soon show symptoms of fatigue in hard water.

 However, if the surroundings are good they can take harder water, as so many snails do.

As I mixed some species there are sand and loamy ground for the soft-substrate dwellers as well as hard substrates like stone structures in my tanks. Gravel proved to be unsuitable. Putting leaves and wood into the aquariums is a must.

All the Tylomelanias kept by me are not compatible with fish.

They also react very sensitively to larger numbers of shrimp, with the exception of two species. Keeping them together with other Tylomelania species and Viviparids is not complicated, they didn't have problems with one or two clams either – neither did the clams, providing they were fed enough.

Additional information:

Tylomelania is on the food list of some crabs in the habitat as well as on that of the local human population. Tylomelania is said to be good against stomach ailments and pregnancy discomfort ;o) – but keep care, don´t  taste them.

I'd like to thank Thomas von Rintelen, Humboldt University Berlin, who took the time to give me further information on these snails as well as text documents of dissertations.