Am I the only one to think the lighting is SOOOOOO off.
Look at the face of the fish. The sun seems to be coming from top left, around 45 deg, from the photographer. On looking at the face of the guy in front, , the sun seems to be coming from the middle/right of the photographer. If that was the case, there would be a bit of light on the rest of the fish.
Also, the guy holding the fish, where is his right hand

Last thing, he is holding the fish, I assume it is a bit slippery so he needs to grab it well. Yet there seems to be no preassure marks (where the skin goes in) on his finger. It seems like the fish is rock hard, which it ain't.
Defo fake.
EDIT: Another bad shadow. Look at the bottom of the fish, now look at the shadow casted on the guy's shirt. The fish's bottom is a bit circular, yet the shadow on the t-shirt is straight. This does, once again, prove my opening point, where I said that the sun seems to come from one side, and thus, the shadow will still be taking the shape of the fish, but a bit more to the side. The shadow shows none of this.
EDIT 2: Now look at the guy behind, he has his hand on the guy in front. If the light was coming from the left of the photographer, the amount of shadow on the front guy;'s shirt would be less (something like I was saying in edit one) but it seems like to be coming from mid-right with the amount of shadow on the front guy.