Boy, Giles certainly makes it sound mysterious and I don't want to dispell that if I don't have to! I can say that smoke and mirrors were certainly involved. Wait a second - smoke wouldn't work underwater.
Actually, what I am talking about is the arm-crossing trick you told me about Alex. I didn't use it to get these shots, but it sure seems like a good idea.
For those of you from Texas, think of firing a handgun with your right hand and bracing across your left forearm (Author's note - I have never fired a handgun). Rather than put a finger down on a piece of rock to the left of your subject, holding the housing w/ the right hand (what I usually do) - place your left hand/finger to the RIGHT of the subject if possible, then rest the housing on your forearm.
How did I get so close to the critters? Well I was just as quiet and calm as could be. Don't blow out a huge burst of bubbles in the critter's face. Approach slowly and move slowly. Fire a shot or two from out past a foot, then slowly move in, half pressing the button as you to in order to maintain focus. Once you lose focus, the Nikkor 105mm can get really lost, and you'll have to move back out and start over again.
Bring your strobes in really tight to the port, like almost touching it. This way you don't bash the coral to the left, right, top or bottom of your subject. Use diffusers.
Shoot, that's all I can think of for now. These are pretty much just general guidelines for shooting macro that I have heard before many times. Except for the forearm bracing trick that Alex told me about.
Cheers
James