[2] Characiosiphon rivularis consists of cylindrical thalli, termed coenocytes, attached to a substrate.

[3] Each coenocyte consists of many small individual regions of the protoplast lining a large vacuole.

Asexual reproduction occurs via the formation of zoospores formed by the division of the protoplast.

In rare cases, aplanospores are formed instead when zoospores lose their flagella while still in the parent thallus.

It can be found attached to a variety of objects including stones, sticks, other plants, and snails.