This large red flabellina (Flabellina trophina) has visibly textured reddish cores in its dorsal gills (cerata). This nudibranch is known for having a long mouth that protrudes forward and is often raised up above the substrate. Another identifying feature is that the rhinophores have rings encircling them. The red flabellina can grow to 4.7 inches (12 cm) long, with a range that includes the Sea of Japan, and southern Alaska to central Oregon.
