To minimize any potential aftertaste, it is generally recommended to take fish oil supplements with a meal. This can help with digestion and reduce the chance of experiencing a fishy taste or burps later. Some people find that taking the capsule in the middle of the meal, rather than at the very beginning or end, works best.
Remember that a mild, characteristic smell of fish oil is natural for this type of supplement and is noted on the packaging. If you are particularly sensitive to taste, you could store the bottle in the refrigerator, as cool temperatures can sometimes help preserve freshness and reduce odor, though you should first check the storage instructions on the product label. If an aftertaste persists despite these steps, it may be a sign of the oil's natural properties.