The purpose of this application, under Article 23.9.3 of the Code, is to conserve the specific name Aiptasia pallida (Agassiz in Verrill, 1864) for a species of sea anemone (Cnidaria, Actiniaria) widely used as a model system for dinoflagellate-cnidarian symbiosis and coral bleaching studies. The name A. diaphana (Rapp, 1829) is a senior subjective synonym of A. pallida, while Aiptasia inula (Duchassaing de Fombressin & Michelotti, 1864), Aiptasia mimosa (Duchassaing de Fombressin & Michelotti, 1864) and Aiptasia tagetes (Duchassaing de Fombressin & Michelotti, 1864) are also synonyms, but published in the same year. The use of the name A. pallida meets the requirements for reversal of precedence of a junior synonym (Article 23.9.1) in the case of A. inula and A. mimosa, which were not used in the 20th century and are declared nomina oblita under Article 23.9.2 in this paper. The names A. diaphana and A. tagetes were used after 1899; hence the conditions of Article 23.9.1.1 are not met. However, in the interest of nomenclatural stability, we request a ruling to maintain the use of the junior synonym under the plenary power, thereby making A. pallida a nomen protectum, and A. diaphana and A. tagetes nomina oblita.