Porella minuta is an encrusting bryozoan that forms small rounded patches, composed of a single layer of autozooids. Autozooids are oval to hexagonal and convex. They are small, typically 0.35-0.4 by about 0.2 mm.
Porella minuta ranges from the western Mediterranean to Shetland. The species is apparently rare in Shetland and likely at the northern limit of its range. It has been recorded intermittently down the western coast of Britain, and occurs at Hastings, the Antrim coast and on shell deposits in the western English Channel.
The species is able to colonise hard substrates and is most often found on small shells in offshore habitats, where the colonies form part of a dense community of bryozoans and serpulid worms on the inner surfaces of bivalve shells.