Composition and metabolism of carotenoids in Daphia pulex and in Artemia salina (from California, Utah, Canada) have been studied. Daphnia contains canthaxanthin and echinenone mainly. The typical pigment of Crustaceae, astaxanthin, is absent. Eggs and freshly hatched nauplii of Artemia from California and Utah have the same qualitative composition of carotenoids as Daphnia. The strain from Canada contains traces of astacene in addition. Artemia has been fed on bakers’ yeast and on algae containing astaxanthin, canthaxanthin, echinenone, lutein, β-carotene, and other polyenes. These experiments demonstrate that Artemia is unable to store or to synthesize astaxanthin — contrary to canthaxanthin and echinenone — from the absorbed carotenoids. After having been fed on algae there is only a small amount of astacene (not astaxanthin!) in the strain from Canada. The metabolism of carotenoids in Artemia salina has been discussed.