Polyp Sponge

Overview

The Polyp Sponge (Mycale fistulifera) is a distinctive, encrusting sponge native to the Red Sea and parts of the Indian Ocean. It is widely recognized for its vibrant red to orange-red coloration and its unique symbiotic relationship with the crown jellyfish Nausithoe punctata.

Appearance

This sponge typically exhibits an irregular, encrusting growth form that can colonize various substrates, including rocks, dead coral, and even large shells. Its surface is generally smooth and features prominent, raised oscules (exhalant pores) bordered by fine membranes. A key identifying feature is the presence of small, white, ciliated circles on the surface, which are actually the polyp phase of the jellyfish Nausithoe punctata residing within the sponge's inhalant pores.

Distribution & habitat

Mycale fistulifera is endemic to the Red Sea and is also found in the Indian Ocean. It thrives in shallow reef environments, commonly occupying rocky or coral-rich substrates at depths ranging from 2 to 20 meters.

Biology & behavior

As a filter feeder, this sponge draws water through its porous body to extract planktonic microorganisms and oxygen. Like other members of the class Demospongiae, it is hermaphroditic and reproduces sexually. It releases free-swimming, ciliated larvae into the water column, which eventually settle on suitable substrates to develop into new sponges.