Nudibranchs are hermaphrodites

Since they are such slow movers, nudibranchs need to be always ready to reproduce whenever they meet another nudibranch, irrelevant of whether the other nudibranch is a male or a female.

Unlike most snails, nudibranchs lack a shell that can be used for protection from predators (they shed their shells as larvae). This means that nudibranchs must defend themselves in other ways. Some nudibranchs use camouflage to blend in with their environments, while others use very bright and contrasting colors to signal to predators "watch out." Many aeolid nudibranchs have evolved the ability to ingest and reuse stinging cells from their prey.

Martadoris Mediterranea

The martadoris mediterranea, can grow up to 10 mm. For a good perspective of its size, in one of the photos, it is shown on my fingertip. Its preferred habitat, is posedonia meadows.

Hypselodoris tricolor

Nudibranchs are considered carnivorous

Their prey include sponges, coral, anemones, hydroids, barnacles, fish eggs, sea slugs, and other nudibranchs. But they are picky eaters and individual species or families of nudibranchs may eat only one kind of prey. This particular one only eats Dysidea, which is a particular type of sponge.

Cratena peregrina

This nudibranch is a kleptopreditor

This nudibranch has a taste for microscopic marine creatures called zooplankton, and it feeds on them using a method that's never been seen before: It captures quantities in a gulp by using hydroid polyps as an unsuspecting helpers

The hydroid polyps are tiny, coral-like animals that live in colonies and gorge on zooplankton. This nudibranch treats the polyps as living fishing nets, avidly scooping them up and swallowing them down as soon as the hapless hydroids finish their zooplankton supper.

Some animals, such as hyenas, are known for a behavior called kleptoparasitism, in which they wait until an animal kills its prey and then drive the predator away to claim its meal. However, this nudibranch behavior — stealing the predator's feast by swallowing the predator and prey together — is something that was previously unknown, and researchers dubbed it "kleptopredation" in a new study.

Flabellina

Did you know that the nudibranch horns are for detecting smell?

These are called rhinophores and can be retracted when under attack.

The branching growth on the back of the nudibranch is a branchial plume and acts like a gill to filter oxygen from the water.