The larval stage, of a crustacean such as the brine shrimp, Artemia salina or brine shrimp. "Artemia nauplii" are commonly used as a first food for fish.

The cells at the tip of an anemones' (corals) tentacles which "sting" when touched.

one of several types of symbiotic relationships between the individuals of two (or more) different species. In a neutral relationship both species are unaffected (see symbiosis).