Underwater Pictures

Does anyone have any advice about post processing of underwater images? This is a quick attempt that I've had so far;



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That fish was about 3 feet long by the way...

I decided to take the plunge, and took my K200D snorkeling- in a Ewa Marine soft case. Most of the shots are natural light (water visibility wasn't good enough to use the FZ360 flash).
I'd be interested if anyone had any advice about techniques to get the most out of these shots.

As an example, here's an unprocessed image;



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Any feedback appreciated. There is some limitation in the flat glass front of the underwater housing, so the pictures are never going to look fantastic....

All I can suggest is adjust the levels tweak the saturation and finally crop and sharpen, if you do anything else its classed as digital manipulation and thats cheating if you need detailed help on how to adjust levels etc then just ask.

As for composition, the "Fat Fish" (I'm not educated like Gareth) is in the right place with room to "swim into" though its a real pity you didn't get its eye.
The "Long Fish" probably wants a crop starting behind its tail and coming diagonally down and right.