This has many identities in Flounder, Tuna and Sole. But the Yellowtail Amberjack is the one used highly in Japan and more common in the pacific U.S.
The meat is pink, though wild Yellowtail can vary in color due to differing fat content among fish. Farmed Yellowtail is consistently light colored because it is high in fat.
Hamachi is a versatile fish. Though mostly served raw, thinly sliced for sashimi, it is delicious lightly seared or marinated and then roasted, grilled.