Individually quick-frozen Herring. Herrings are a complementary food and are, among other things, extremely suitable for use in a BARF diet in combination with organ meat, meaty bone, and muscle meat. The herring (Clupea harengus) is a fatty saltwater fish rich in omega-3 fatty acids. Our herring is approximately 12 to 15 cm in size and is caught in the Northeastern Atlantic Ocean. IQF means that it is frozen separately. The herrings can therefore be thawed one by one. Herring is very rich in omega-3 fatty acids and vitamins that are much less common in meat. Caution: Fatty fish species contain the enzyme thiaminase which breaks down vitamin B1. It is therefore recommended not to give fatty fish to a dog more than once a week.