Nudibranchs/Sea Slugs

Nudibranchs, commonly known as sea slugs, are a group of shell-less marine mollusks. Their name means ‘naked gill’, referring to the breathing apparatus on the outside of their soft bodies.

Generally oblong in shape, nudibranchs can be thick or flattened, long or short, ornately colored or drab to match their surroundings. They can grow as small as 0.25 inches or as large as 12 inches long.

They are carnivores that slowly ply their range grazing on algae, sponges, anemones, corals, barnacles, and even other nudibranchs. To identify prey, they have two highly sensitive tentacles, called rhinophores, located on top of their heads. Nudibranchs derive their coloring from the food they eat, which helps in camouflage, and some even retain the foul-tasting poisons of their prey and secrete them as a defense against predators.

Some nudibranchs are poisonous so it’s better not to touch them. Even if they aren’t poisonous, touching one could nearly squeeze, squish, and suffocate it to near of simply, death. Some nudibranchs are poisonous while others pretend to be. They feed on stinging cells of hydrozoids and store them in the rear of their body for protection. They can also ingest toxins from sponges and become toxic and inedible.

Another great fact is that nudi’s are both genders! They aren’t exactly male or female. This comes in very handy, as finding a mate can be a very, very frustrating task for the little slugs. However, they still require a mate in order to reproduce, as they are not able to self-fertilize.