Common name: Pen Shells

Pinnidae, commonly known as pen shells, are a family of large, marine bivalve molluscs. They are characterized by their elongated, pen-like shape and can grow quite large, making them a unique addition to spacious marine aquariums. Pen shells are filter feeders and help maintain water quality by consuming suspended particles. They often host a variety of symbiotic organisms, including small fish and crustaceans, which can add to the biodiversity of a reef tank. However, their size and sedentary nature require careful placement to avoid disturbing other inhabitants.

1. Common name: flag pen shell

   Scientific name: Atrina vexillum