It's neither dead (the eyes are quite lively and you can see that it's suspended) nor manipulated. I've been using Photoshop on pictures for years and it gets quite easy to tell when something has been tampered with, especially on something that I'm very familiar working with like fish pictures.
I've been stalking this thread wanting to know what it is too. Being both a nerd and also curious about this adorable fish, I did some sleuthing.
It appears to be a new/as yet unnamed fish from Japan. Thankfully the OP hot linked, which shows that the image is from an index on a website for the University of Miyazaki. There are other images of the fish (which they don't identify) as well as a few pages talking about new fish.
The other pictures:
They were all taken around May 16, 2008. There was a page with a brief caption (in Japanese) where they seem to refer to it as "figure 1" and give details about where it was found, so I assume it's new. I'm not sure how long it takes or what the process is to name them. Is it possible that they're still working at it after 2 1/2 years?
Anyways, I suppose I should be grateful that it's not something available because I think they're gorgeous and want one.
No wonder the poor OP was going crazy trying to figure out what it is!