Tylomelania sarasinorum

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Tylomelania sarasinorum, also called Poso Yellow Rabbit Snail, is a freshwater gastropod from the Indonesian island of Sulawesi. This snail from the family Pachychilidae is recognized by its elongated shell, often yellow to orange body, and calm grazing behavior on aquarium surfaces. Associated with Lake Poso, it belongs to Sulawesi’s remarkable freshwater fauna. The specimens offered here are collected from the wild, so acclimation deserves particular attention, especially regarding temperature, mineral stability and the availability of varied vegetable foods. A mature aquarium that provides oxygenated, stable water and natural biofilm will help this distinctive snail settle successfully.

General species description

Tylomelania sarasinorum is an operculate freshwater snail of the genus Tylomelania, a particularly diverse group found in Sulawesi’s inland waters. The species is associated with Lake Poso and its littoral habitats, where it moves across rocks, wood and organic debris. Its activity is mainly crepuscular and nocturnal, although a well-acclimated specimen may also move during the day. Like other rabbit snails, it travels with a broad muscular foot and uses its radula to graze on biofilm. It is not a specialized algae eater capable of cleaning an aquarium on its own, so supplemental feeding is necessary. A mature aquarium with good oxygenation and biologically active surfaces is preferable to a newly established tank. It is common in the specialist aquarium trade, but individual wild specimens may respond differently after shipping.

Geographical origin and biotope

The country of origin is Indonesia, specifically the island of Sulawesi. Tylomelania sarasinorum is associated with the basin of Lake Poso, an ancient tectonic lake with generally clear, mineral-rich water. In this type of habitat, snails use shallow areas where rocks and sediment provide grazing surfaces. The biotope includes hard substrates, fine deposits and accumulations of leaves or plant debris. Dense vegetation is not required everywhere, but plants, algae and biofilm increase the available food supply. In an aquarium, stable neutral to alkaline water with adequate calcium is recommended for shell growth and maintenance. Because the offered specimens are wild collected, slow acclimation and close observation are advisable. Avoid rapid changes in temperature, pH and conductivity.

Precise location and local name

The reference locality is Lake Poso, in Central Sulawesi Province, Indonesia. The English trade name Poso Yellow Rabbit Snail directly recalls its geographical origin and its usually yellow to orange coloration. The term “rabbit snail” is an aquarium name referring to the elongated head and long sensory tentacles of these gastropods rather than to a traditional Indonesian name. In the trade, Tylomelania sarasinorum may also be sold under its scientific name or under a shortened designation connected with Poso. Since several Tylomelania species have similar forms and colors, the commercial identification should be considered together with the stated locality. Provide quiet areas, rocky grazing surfaces and shelters, while maintaining sufficient water movement. Clean, well-oxygenated water should be a priority.

Appearance and physical characteristics

Tylomelania sarasinorum has a tall, elongated conical shell, often dark brown to black, with variation in texture and coloration among individuals. The body is generally yellow, cream or orange, which explains the trade name. The head carries two prominent sensory tentacles, and the broad foot is adapted for movement across solid surfaces. An operculum allows the animal to close the shell opening when conditions become unfavorable. The combination of a yellow to orange body and dark shell makes this species especially distinctive in a planted aquarium. Adult specimens may reach approximately 8 cm, depending on lineage, age and maintenance conditions. Water that is too acidic or mineral-poor can weaken the shell. Avoid sharp decorations and repeated handling, since both the foot and shell can be damaged.

General diet

In nature, Tylomelania sarasinorum mainly grazes on biofilm, fine algae and organic deposits growing on rocks, wood and other surfaces. In an aquarium, these natural resources should be supplemented with sinking foods containing spirulina and vegetables. Small portions of blanched zucchini, cucumber, romaine lettuce or spinach may be offered and removed before they decompose. A regular source of calcium helps maintain the shell; sufficiently mineralized water, complete invert foods or an appropriate mineral supplement may be used. This species is not predatory and should not be treated as a solution for excessive algae growth. Feed moderately, especially in a mature aquarium, to prevent waste accumulation. Observe activity and shell condition to adjust portions and maintain good long-term health.

Essential data

• Name of source river: Lake Poso and its associated basin
• Local name used: Poso Yellow Rabbit Snail
• Origin of the scientific name: The genus Tylomelania and the specific epithet sarasinorum
• Etymology of the full name: Tylomelania refers to the genus established for these snails; sarasinorum honors the brothers Paul Sarasin and Fritz Sarasin
• Common/vernacular names: Poso Yellow Rabbit Snail; yellow Poso rabbit snail
• Family: Pachychilidae
• Subfamily: Not specified
• Name pronunciation: tie-loh-meh-LA-nee-ah sah-ra-see-NOR-um
• Discovery: Paul Sarasin and Fritz Sarasin, 1897
• Maximum adult size: Approximately 8 cm
• Water temperature and pH: 26 to 30 °C; pH 7.5 to 8.5
• Watercourse appearance and surrounding vegetation: Clear water, rocky substrates and littoral areas with biofilm, algae and plant debris
• Typical tankmates: Peaceful snails, compatible freshwater shrimp and small non-predatory fish
• Temperament and behavior: Peaceful and slow-moving, mainly crepuscular and nocturnal; grazes on surfaces
• Water depth: Littoral and shallow areas
• Sexual dimorphism: No reliable external dimorphism commonly used in aquaria
• Bottom structure and flow: Rocks, sand or fine sediment and plant debris; low to moderate flow with good oxygenation

In your aquarium

To succeed with Tylomelania sarasinorum, use a mature aquarium with warm, stable and mineral-rich water, along with a bottom free of sharp edges. Provide grazing surfaces, supplemental vegetable foods and a calcium source. Since these are wild-collected specimens, slow acclimation is especially important. Avoid copper-based treatments, sudden changes and tankmates capable of attacking snails. Efficient filtration, moderate current and good oxygenation will encourage regular activity and help maintain a healthy shell.