(<i>snapshots</i> disclaimer - excuse the non-l33t photo skillz)

Some stuff comes out pretty clear, like:

this sand diver
<img src="http://farm1.static.flickr.com/156/377253198_8dce32c49d.jpg?v=0">

queen angelfish
<img src="http://farm1.static.flickr.com/154/377253200_05c7f52a13.jpg?v=0">

and purple tipped anemonenenenene
<img src="http://farm1.static.flickr.com/175/377235521_cef1a4c20a.jpg?v=0">

conch leaving a snail trail
<img src="http://farm1.static.flickr.com/185/377235513_00030a64a3.jpg?v=0">

and sea cucumber.
<img src="http://farm1.static.flickr.com/155/377253206_3d7b93f7af.jpg?v=0">

Other stuff was a bit overly blue/green:

trumpet fish (this was at roughly the same depth as the pics above)
<img src="http://farm1.static.flickr.com/177/377235515_eb48994fd5.jpg?v=0">


great barracuda (it's a bit fuzzy from the distance, but I wasn't gonna try to swim closer)
<img src="http://farm1.static.flickr.com/150/377253208_8a20adfa4f.jpg?v=0">

'nother 'cuda, at a deeper depth, so the blueness is sort of understandable.
<img src="http://farm1.static.flickr.com/186/377235527_968cc32a67.jpg?v=0">

And at the same depth, this spotted eagle ray looked fine
<img src="http://farm1.static.flickr.com/165/375721807_161a740751.jpg?v=0">
whereas this peacock flounder looks sort of overly aqua
<img src="http://farm1.static.flickr.com/131/379002957_27245c8ea0.jpg">

if it gives you the option to adjust manually, take a white slate or something underwater, and adjust w/b while you're down.
other than that, unless you're shooting raw and or have a big strobe, you're limited to close shots. macro can be fun though.

what kind of camera and where were those shots taken?

it is possible to adjust w/b from a jpeg but the results aren't really that great. try picasa and play with the w/b there.

Now that you mention it, I vaguely remember someone posting something either here or in dpreview that would be useful - just a small piece of white plastic to use for such a purpose, that could be stuck on the wrist strap or something. The less stuff dangling about and/or being carried, the better IMO.

Shot with a SD600 in the associated Canon waterproof case. I guess flickr strips off the exif when it resizes - it shows up on the full sized pic.

Taken in/near Belize. A few more pics <a href="http://forums.audiworld.com/other/msgs/6669657.phtml">here</a>