Felimare marci is a species of sea slug or dorid nudibranch, a marine gastropod mollusc in the family Chromodorididae.

[3] This nudibranch is found in the Western Atlantic Ocean and the Caribbean from Brazil to Venezuela.

[1] It was also identified by Marcus from Ilha dos Porcos, Cabo Frio in southern Brazil.

[4] Felimare marci has a body colour of pale yellow-green covered by bright blue spots of various shapes and sizes.

(description of the synonym) Hypselodoris marci has a golden-brown body covered with many small blue or black spots.