- Frozen South Atlantic flathead fillets - Source of protein - Good source of Omega-3 - Serve with tartar and steamed vegetables I&J Flathead Fillets are a good source of Omega-3 and a source of protein. Serve with a side of roasted veggies or crispy potatoes for an easy dinner. I&J Flathead Fillets make it easy to prepare a delicious fish meal. Try them with crispy potatoes or roasted vegetables on the side and top with classic tartar sauce for an extra kick of flavour. Tasty and easy to prepare, I&J Flathead Fillets are a great addition to a variety of fish-based recipes. These offer a mild, slightly sweet flavour and are also a good source of Omega-3 and a source of protein. For an extra addition of flavour and texture, try coating your fillets with breadcrumbs, polenta, flour or dried herbs.