Most aquarists will never see this group (Phylum) of advanced invertebrates. Not only are they small and cryptic by nature, as a consequence of these qualities and the vagaries of wild collection and shipping, bryozoans just "don't make it" from reefs to homes. Just the same, because there are folks who endeavor to keep and culture most everything, and there are cases where these "moss animals" have survived the rigors of the trade, we will discuss them.

    Often looking more like algae than animals the Bryozoa are small, encrusting, branching colonial animals. Colonies are made up of individual zooids of about 1/25 of an inch in length. This basic building block (the zooid) builds a chitinous or calcareous house around itself and between its kin. The resultant structures look bushy, like webs, fans, branches... and are flexible to rigid.

    Like some closely related groups/phyla the zooids filter feed by way of a tentacular crown called a lophophore. The bryozoans other scientific name refers to the placement of their anus. Food is directed by cilia on the tentacles into a mouth, through a simple digestive tract (one-way), and exits outside the ring of tentacles. Notable for the group are specialized defensive zooids termed avicularia (like aves, bird for their beak-like heads).

    Along with groups like sponges, sea squirts, barnacles and many hydroids and worms, the Bryozoa are important components of "fouling communities"... living in silty harbors, boat bottoms... Due to such tolerance and beauty, there should be a future in advanced marine aquarist's tanks for this group.

Range:

    Worldwide in tropical to temperate seas, some freshwater. About 5,000 described species.

Species on Parade!

Bibliography/Further Reference:

Gosliner, Terrence M, Behrens, David W. & Gary C. Williams. 1996. Coral Reef Animals of the Indo-Pacific. Sea Challengers, Monterey, California. 314pp.