This study examined the effects of dietary esterified astaxanthin concentration
on coloration, accumulation of carotenoids, and the composition of carotenoids over time
in the skin of Amphiprion ocellaris. Juveniles of 30 days-post-hatch were fed 40, 60, 80, or
160 mg esterified astaxanthin per kg diet (mg kg-1) for 90 days. Skin coloration was
analyzed using the hue, saturation, and luminosity model. Increased astaxanthin concentrations
and duration on diet lead to improvements in skin color, that is, lower hues
(*27–29 to *14–17; redder fish), higher saturation (*77 to *87 %), and lower luminosity
(*43 to*35 %). Fish fed 80 and 160 mg kg-1 astaxanthin feed showed significant
coloration improvements over fish fed lower astaxanthin feeds. Increasing both dietary
astaxanthin concentration and time on the feed resulted in significant increases in total skin
carotenoid concentration (0.033–0.099 lg mm-2). Furthermore, there was a significant
linear relationship between hue and total skin carotenoid concentration. Compositionally,
free astaxanthin and 4-hydroxyzeaxanthin were the major skin carotenoids. 4-hydroxyzeaxanthin
was previously unreported for A. ocellaris. Carotenoid composition was
affected by duration on diet. Fraction 4-hydroxyzeaxanthin increased by *15 %, while
free astaxanthin decreased equivalently. The transition from 4-hydroxyzeaxanthin to free
astaxanthin appears to follow a reductive pathway. Results suggest that managing coloration
in the production of A. ocellaris juveniles requires manipulation of both dietary
astaxanthin concentration and period of exposure to astaxanthin containing diet. In order to