After extraction of astaxanthin with viscozyme and absolute alcohol, the nutritional composition of Haematococcus pluvialis residue remained 35.5 % protein, 14.9% fat, 36.8 % glucide, 4.48 % crude fiber and 0,69 % astaxanthin. Algal residue treated by mechanical grinding combined with 0.1M NaOH showed the highest extraction efficiency of astaxanthin (72.16 %) when compared to other methods: mechanical grinding combined with 0.1M HCl (54.75 %), olive oil solvent combined with autoclave (59.26 %) and water solvent combined with autoclave (30.54 %). The addition of astaxanthin-containing microalgae residue in the feed at concentrations of 50mg astaxanthin/kg, 100mg astaxanthin/kg and 150mg astaxanthin/kg has the effect of enhancing red pigmentation for Japanese Koi fish after 14 days of investigation.