Pollock can be distinguished by their greenish coloring, and have a white lateral line. They have a slightly stronger flavor, with a larger and firmer flake. Haddock, on the other hand, have a black lateral line and can be distinguished by a black “thumbprint”on the side of their body. They have a finer flake and more mild flavor.
White hake, is not a part of the same family, though is in the same order (Gadiformes). They have a more slender body with softer flesh. And then there’s the Silver Hake, also known as Whiting, which is significantly smaller, averaging 1/2-1lb each. They are silvery in color with sharp teeth. Their flesh is softer and less flaky, and they’re best cleaned up and fried whole.