Offers' snail
Astraea olfersii
Astraea olfersii has a thick conical shell, often adorned with brown and white spiral bands. Adult size reaches about 2-3 cm in diameter. It moves slowly over rocks and glass, grazing on filamentous algae and diatoms. Mostly active at night, it hides in crevices during the day. Its muscular foot allows it to cling firmly even in moderate currents. It is completely harmless to corals and fish. When stressed, it may release a protective mucus.
Recommended parameters
| Parameter | Recommended range |
|---|---|
| Temperature | 22–28 |
| pH | 8.1–8.4 |
| GH | 7–9 |
| KH | 8–12 |
| NO₃ | ≤ 20 |
| PO₄ | ≤ 0.1 |
Care
Care notes
Maintain temperature 22-28°C, pH 8.1-8.4, salinity 1.023-1.025. A well-established aquarium with live rock and natural algae is ideal. A minimum tank volume of 40 liters is recommended for a small group. Diet is primarily herbivorous: it feeds on existing algae, but can be supplemented with dried seaweed (nori). Avoid high nitrate (>20 ppm) and phosphate (>0.1 ppm) levels. It is compatible with all peaceful fish and invertebrates. Beware of predators such as pufferfish or crabs. Slow acclimation is necessary to avoid stress.