The invention describes previously undisclosed crystal forms of astaxanthin designated crystal form I and II. It has been surprisingly found that the two crystal forms of astaxanthin show an improved bioavailability, a relatively high solubility in specific organic solvents and an increased long-term stability. For example the new forms are stable in solid form for at least 90 days at a temperature of 20° C.-40° C. It was further found that the two crystal forms can be prepared from each other. Therefore the invention also relates to methods for preparing said crystal forms. In addition, the invention relates to administration forms (hereinafter also called “formulations”) comprising one of the two crystal forms according to the invention or mixtures thereof dissolved or suspended in oil or organic-solvent.