An urgent need exists to identify suitable tropical marine species for use in the development of sensitive and reliable test methods for routine laboratory ecotoxicological testing. Corals are a group of organisms not represented in routine ecotoxicology due to inherent difficulties in laboratory husbandry, and sea anemones from the same phylum (cnidaria) may be useful proxies. Aiptasia pulchella is a tropical symbiotic sea anemone with a wide geographic range. It is well suited to laboratory conditions and has been used extensively in research. However, its suitability as a toxicity test species has not been investigated. Assessment of juvenile recruitment in laboratory and semi‐outdoor conditions showed higher production in semi‐outdoor conditions; however, laboratory rearing produced enough recruits to run routine toxicity tests. In investigations of the sensitivity of A. pulchella to contaminants, acute tests were conducted on 1‐ to 2‐mm juveniles using copper. Lethal concentration, 50% (LC50) values at 96 h estimated from tests using five and 10 replicates ranged from 30 to 83 and 60 to 90 µg/L, respectively, and a 28‐d LC50 of 26 µg/L was estimated. During the present study, sublethal endpoints were investigated; chronic assessment of inhibited asexual reproduction looks promising (12‐d effective concentration, 50% [EC50] 15 µg/L) and should be assessed further. Aiptasia pulchella is a species worthy of investigation as a cnidarian representative, and will be an invaluable contribution to tropical marine ecotoxicologists. Environ. Toxicol. Chem. 2012; 31: 2653–2662. © 2012 SETAC