Colonies of Electra pilosa form broad mats or star-shaped patches on the surface of the fronds of large algae such as Laminaria and Fucus serratus.

The zooids also grows in small patches or tufts on the surface of shells and stones, and encircling the fronds of red algae such as Mastocarpus stellatus.

The calcified protective covering bears about nine spines (four to twelve), the central one being much longer than the others, giving the colony a hairy (Latin pilosa) appearance.

[3] In common with other bryozoans, Electra pilosa filter feeds with the aid of a crown of tentacles known as a lophophore with which it sieves particles from the water.

The spines on the exoskeleton, especially the long one, offer protection to the zooid when it is feeding and may grow longer in colonies facing competition from other bryozoans.