ensia

Ensia is a genus of ray-finned fish belonging to the family Pomacentridae, commonly known as damselfish. These fish are native to the tropical waters of the Indo-Pacific region. Ensia species are generally small, often brightly colored, and inhabit coral reefs where they feed on algae and small invertebrates. They are known for their territorial behavior, often defending a specific area of the reef.

The genus Ensia was first described by ichthyologist David Starr Jordan in 1887. While the genus has historically been recognized, taxonomic revisions are not uncommon within fish classification, and Ensia's placement within Pomacentridae has been subject to ongoing research. Current understanding generally places Ensia as a distinct lineage within the damselfish family, though some older classifications might include its members in broader genera.

Species within Ensia are typically characterized by their laterally compressed bodies and a single, continuous dorsal fin. Their coloration can vary, with some species exhibiting vibrant blues, yellows, or oranges, often with distinct patterns. These fish play a role in the reef ecosystem by grazing on algae, which helps maintain the health of coral structures. Their small size and schooling behavior in some species also make them a food source for larger predatory fish.