The difference between fish steak and fish fillet is the cut. If the flesh of the fish is cut whole to separate it from the bone, then, you have a fillet. So, what you see in the photo above is a fillet.
And, below, another fish fillet dish.
If the fish is cut cross-wise, cutting through the bone, the resulting cut is a fish steak.
Above and below are two fish steak dishes.
Why choose fish steak over fillet or the other way around?
Some say that in fine dining, you can’t serve the fish with the bone. Which is really a shame because the richest flavors of the fish are in the bone. If you cook the fish with the bone, the meat soaks up all the goodness from the bone. If you separate flesh from bone, as you do with fillets, you lose that opportunity to enjoy what the bone has to offer.
So, fish steak is preferable over fillet? Not all the time. There are recipes that you’ll find impossible to execute unless you use fillets. Like? Fish and chips, for one. Another consideration is the size of the fish. If the fish is really large and a cross-cut is too much for a single serving, then, fillets will probably be more practical.
All the photos are clickable, by the way, if you want the recipes for the fish dishes that you see.