The green feather alga, Caulerpa sertularioides, is among approximately 35 species and varieties of Caulerpa found in the Caribbean and western Atlantic Oceans (Littler & Littler 2000). The alga obtains its name from the feather-like fronds rising from a common stolon. Each frond is upright, branched and light to dark green in color (Littler & Littler 2000, Littler et al. 2008, Taylor 1979). Branchlets are opposite, cylindrical and needle-shaped with upcurved or straight apices or tips that are bluntly pointed. Each branchlet, measuring 180-330 ¦#181;m in diameter and 3-11 mm long, is connected to a central, cylindrical axis measuring 1.0-1.5 mm in diameter. These axes connect each frond to a creeping stolon, 2.0-2.5 mm in diameter and up to 2 m long. Stolons branch to slender points and rhizoids stem from the ventral or bottom surface of each stolon to hold the alga to the substrate.