Both krill oil and fish oil are beneficial to people because they add omega-3 fatty acids to the diet; however, fish oil has a significantly longer life, according to Brad Sly for Breaking Muscle. This allows more time for processing.
Krill oil and fish oil, as dietary supplements, have healthful benefits provided the supplements are of good quality. Krill contains the antioxidant astaxanthin, but this supplement begins to decompose in only two to three hours, notes Sly. Fish oil also contains antioxidants but lasts 48 to 72 hours before decomposition and oxidation occur. Adding vitamin E and rosemary extract to each is the most effective way of maintaining freshness in the oil. Both are lipid lowering and reduce pain from arthritis.