iPhoto and Nikon's Capture NX.
Not an Adobe kind of a guy.
The first one is down about 25 feet and it was getting pretty dark, about 6 feet away from the wall...
The second one is actually quite near the surface, shot with the 'el cheapo' Sealife wet lens (which actually isn't that bad) but I had it on wrong so there was a bit of vignetting (which is why I cropped to a DSLR aspect ratio). The fish is a four incher or so, and the total distance to the hole in the background is about a yard more or less... I was about 4 feet down when I shot this, over a shelf of rock and muck, and keeping buoyant with my tank only about a foot below the surface and not screwing the vis was tricky.
The first one, I desaturated and burned the background a bit (there was little backscatter), the second one I removed some backscatter and lightened the back half of the fish a bit.
The third one, I burned the hole behind the fish to the upper right down to black since it was very ugly looking and distracting, cleaned off some backscatter and also I darkened the rock in front and desaturated it a bit.
Number 4 is cropped a bit and I sharpened the fish just a bit in the body and added some contrast.
Number 5 is a vertical crop of a horizontal shot. There was a lot of backscatter in the corners, so rather than spend an hour cleaning it up I just used gausian blur and nuked everything except the fish and the log.
In case you are wondering, I am an experienced land photographer... I have 20,000 or so of my shots online on my Zoopictures.net website, and then I have my Big Island project (which includes a few of my pathetic first attempts at ocean photography... please don't laugh when you see them)... My Blue Hawaii