Microscale pigment adjustments to a tropical photosynthetically active radiation and ultraviolet (UV) environment by the intertidal turf algae Ahnfeltiopsis concinna and Laurencia mcdermidiae were promoted by thalli densities that self-shade the understory portions of the same diminutive axes. Tissues of A. concinna from canopy microsites had significantly reduced levels of phycoerythrin, phycocyanin, and allophycocyanin compared to tissues from understory microsites of the same axes. Tissues of L. mcdermidiae from canopy microsites had reduced levels of only phycoerythrin compared to tissues from understory microsites. A pattern of remarkably sensitive photoacclimation over the ≤ 10-cm axes of these turf-forming rhodophytes was indicated.