Tuna steak is a cut of fish taken from the tuna, a large and powerful fish found in oceans worldwide. It is known for its firm texture and rich flavor, making it a popular choice for grilling, searing, or even serving raw in dishes like sushi and sashimi. Tuna steaks are typically sold in thick slices and can vary in color from deep red to pale pink, depending on the species. They are a good source of protein and contain essential nutrients, including omega-3 fatty acids, which are beneficial for heart health.