Although often used decoratively in flower arrangements, flowerpots and aquariums, air ferns--also commonly referred to and sold as "air plants," "air moss," "air firs" "Irish Sea Fern" and "Neptune plants"--have no actual relationship to the plant kingdom beyond their outward appearance. In reality, the fernlike branches consist of remains/skeletons of dead, tiny marine animals (typically sertularia or bugula), similar to corals and jellyfish, that trawlers harvest from the sea and then sell to vendors, who dye them red or green to mimic ferns. As air ferns don't need soil, plant food, fertilizer or water, they can make an ideal artificial plant decoration and, as a result, require little care or maintenance.
Place your air fern in an open, well-ventilated area as the dead fernlike branches have a distinctive bad odor unless pre-treated with a fragrance for non-aquarium use (for example, florist arrangements). If using for an aquarium, place in your tank immediately after un-packaging.
Move your air fern to an area out of direct sunlight as the branches can bleach under direct sunlight and cause any dyes pre-applied to them to fade.
Dust your air fern lightly with a feather duster or place in an open window on a windy day to remove dust as the fine texture of the fernlike branches can break if roughly rubbed with a cloth or vacuumed.