This may not be the correct forum, but "The Big Pacific" on PBS has 3 episodes, each with some really good underwater photography. I am currently watching the third, and I believe, the last episode, the first segment of which is a detailed background piece on how they set up and took the underwater photography sequences of the puffer fish building their phenomenally ornate nests. This may be old hat to the really good photographers on this board, but I found it to be very good watching.