The colonies are generally small, no more than a few centimeters across, but some in Siphonophorae can reach sizes of several meters. They may have a tree-like or fan-like appearance, depending on species. The polyps themselves are usually tiny, although some noncolonial species are much larger, reaching , or, in the case of the deep-sea Branchiocerianthus, a remarkable 2 m (6.6 ft).
