Bottom line...what you deem as fake may not be. Personally, I can see how the picture in question is possible (i.e. no reflections of the fish).
So...without seeing the setup of the shot and/or talking to the photographer (Amano himself?), it's (IMO) useless to argue fake or real.
Is it a growing trend to manipulate pictures? Sure is. In some cases you get more accurate colors. In others blemishes are removed. And then there are the times when the pictures are just plain fake. And yes, it is possible to manipulate pictures when using regular film, either through multiple exposures or combining pictures or adjusting exposure times for only portions of a picture.
I'm going to push the I believe button on this beautiful aquascape.