Can Canthaxanthin Intensify The Color of the Blood Swordtail Xiphophorus helleri?

The coloring has a great influence on the commercialization of ornamental fish. The aim of this study was to evaluate different concentrations of canthaxanthin in the diet of the blood swordtail Xiphophorus helleri, to obtain a more intense red color. Six concentrations of canthaxanthin (0, 50, 100, 250, 400 and 600 mg kg -1 diet) were used. The experiment lasted 60 days. Fish were evaluated for increased red pigmentation through the use of photographs (performed by smartphone) and imaging applications considering the Hunter method and the CMYK and productive performance. No significant differences were observed for productive performance. The use of photographs by means of a smartphone and the use of imaging applications proved to be adequate to assess differences in color in the species. Swordtail red pigmentation did not show significant increase regardless of canthaxanthin dosages. Varieties of ornamental fish bred for red coloration may have limits for increased color due to the storage capacity of carotenoids by chromatophores.