The Blue Velvet Nudibranch is black in color with blue lines around the outside of its body and down the middle of its head.
It has a hammer shaped head and two appendages at the rear, mimicking a flatworm.
This specialized eater will consume flatworms in the aquarium. It sucks up the flatworms using a tube-like proboscis and makes a great natural alternative for flatworm control. However, it must be provided with a steady diet of flatworms in order to thrive.