Anthopleura aureoradiata, also known as the small brown sea anemone, is a small anemone about 10 mm wide in diameter and very brown in colour. It is native to the waters around New Zealand. The brownish tinge of its outer surface makes it much harder to distinguish and find unlike some of the other sea anemones. This particular class of anemone can be seen under water as a small brown ring in soft fine sediment and slightly submerged. This brown anemone has quite a high tolerance to changes in salinity and to a high concentration of organic matter in the water.