Doriprismatica sedna is a species of colorful sea slug, a dorid nudibranch, a marine gastropod mollusk in the family Chromodorididae.

[2][3] Originally described from the Eastern Pacific, records from the Caribbean are considered the result of a recent introduction, presumably human-introduced.

[3] The indigenous distribution of Doriprismatica sedna includes Eastern Pacific: from the Gulf of California to the Galapagos Islands and non-indigenous in the Western Atlantic: Florida, Belize, Bahamas[4] and Panama.

[8][9][10][3] Upper half of the rhinophoral clubs and tips of the branchial leaves of the gill are red.

[3] By examining the stomach content and feces, they found that this species feeds exclusively on spiculated demosponges and exhibits a variable diet, which includes 17 different species:[3] Mycale psila, Microciona sp., Myxilla incrustans, Lissodendoryx isodictialis, Haliclona caerulea, Haliclona turquoisia, Callyspongia californica, Cliona californiana, Cliona amplicavata, Cliona flavifodina, Cliona papillae, Pione mazatlanensis, Pione carpenteri, Tethya taboga, Aaptos niger, Geodia media and Dysidea uriae.