Is it okay to freeze fish oil to keep it from becoming rancid?
As noted in ConsumerLab.com's Fish Oil Supplements Review (which includes tests and comparisons of fish oil supplements), you can certainly freeze fish oil. This will not adversely affect the oil and will help keep it fresh. For more about this and for other tips when buying and using fish oil, see the Review's ConsumerTips section>>.
Also see ConsumerLab.com's answers to these related questions: