The main carotenoids of four species of copepods found in the Great Barrier Reef have been separated by chromatographic techniques including reversed-phase HPLC and identified using chemical and spectroscopic methods and by mass spectrometry. The carotenoid component of the bluish caroteno-protein complex isolated from all four species was astaxanthin. The predominant carotenoids in Euchaeta russelli were phoenicoxanthin, β-doradexanthin, astaxanthin and its esters while in the other three species (Centropages furcatus, Undinula vulgaris and Temora turbinata), astaxanthin and its esters were the most abundant. The following carotenoids have been characterised on the whole animal: astaxanthin and astaxanthin esters from Centropages furcatus, Undinula vulgaris and Temora turbinata; Euchaeta russelli was found to contain canthaxanthin, astaxanthin and astaxanthin esters, crustaxanthin, phoenicoxanthin, β-doradexanthin, β,β-carotene-3,3',4-triol, and 2'-norastaxanthin ester. This is the first report on the occurrence of 2'-norastaxanthin ester in crustacea. The transformation of astaxanthin or its esters to 2'-norastaxanthin ester is discussed.