Black-margined Nudibranch

Overview

The Black-margined Nudibranch (Doriprismatica atromarginata) is a widely distributed sea slug found throughout tropical and subtropical waters of the Indo-Pacific. Often affectionately called the "cheesecake nudibranch" due to its distinctive coloration, this species is a favorite among underwater photographers for its elegant, high-contrast appearance.

Appearance

This nudibranch typically features a creamy-white to pale brown body, though coloration can vary by region. Its most defining characteristic is the striking black line that borders the highly sinuous, ruffled edge of its mantle. This black edging also highlights the tips of its feathery gills and the clubs of its rhinophores. As it moves, the frilled mantle often ripples like waves, creating a mesmerizing visual effect.

Distribution & habitat

This species is common across the Indian and Pacific Oceans, including regions such as the Red Sea, East Africa, Japan, the Philippines, Indonesia, Australia, and Hawaii. It is primarily found in coral reef environments, often inhabiting rocky substrates, ledges, and caves along outer reef slopes.

Biology & behavior

As a dorid nudibranch, it possesses a feather-like plume of gills on its back. These gills are known to rhythmically wave as the animal crawls, a behavior believed to assist with respiration. Like other members of the Chromodorididae family, it is a hermaphrodite. It lays its eggs in a characteristic spiral ribbon attached to the substrate.

Feeding

This nudibranch feeds on various species of sponges. It is capable of sequestering toxic chemical compounds from its prey, which it incorporates into its own tissues as a defense mechanism to deter potential predators.