Stiliger and Costasiella Sea Slugs Sharing Algae Blade Tip in Bali

A high-magnification macro underwater photograph captures a rare, co-occurring pair of distinct sacoglossan sea slug species perched on the tip of a vertical green algae blade in Bali. Dominating the upper apex is a vivid Stiliger species, displaying a dense, rounded cluster of bright yellow cerata adorned with striking dark blue-and-black ringed ocelli. Clinging directly below it on the same algal margin is a tiny Shaun the Sheep nudibranch, showcasing its pale head, dark-tipped rhinophores, and speckled green cerata. The vertical composition highlights the micro-ecological overlap between two iconic sap-sucking sea slug species on their preferred algal substrate (Avrainvillea species). The shallow depth of field keeps both mollusks and the blade edge sharply in focus against a soft, luminous bokeh of sandy volcanic sea floor and ambient water column. Ideal for marine invertebrate ecology, sacoglossan interspecies behavior guides, educational textbooks, and professional stock media.