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Marine Animal Encyclopedia

Top Shell Trochus niloticus

Easily distinguished from most other gastropods by the conical shape of its spiral shell, the top shell moves slowly over reef flats and coral rubble, feeding on algae. Demand for its flesh and pretty shell has led to declining numbers, especially in the Philippines, due to unregulated harvesting. It has, however, been successfully introduced elsewhere in the Indo-Pacific, such as French Polynesia and the Cook Islands, from where some original sites are being restocked.

Top Shell habitat mapzoom image
  • Class Gastropoda
  • Length 6 in (16 cm)
  • Habitat Intertidal and shallow subtidal areas, reef flats to 23 ft (7 m)
  • Distribution Eastern Indian Ocean, western and southern Pacific