Most if not all adults are sessile, filter-feeding organisms (although some solitary species are capable of slow movement). Some species produce eggs which would hatch into planktonic larvae. These are free-living at first, but will soon settle down into sessile adults. About 156 species are classified under Loxosomatidae, the only family consisting solely of solitary species. The remaining 39 species are colonial. Solitary species are commonly found attaching commensally to various hosts, including sponges, sessile tube-dwelling polychaetes, and bryozoans. The distribution of colonial species is more diverse, as they are found attaching to a wide variety of substrates, including rocks, shells, and algae. Only two species have been documented to live in freshwater. A handful of species live in brackish water, while the remaining large majority are exclusively marine.

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