Jano, this is a lovely, lovely idea, it's really only the lack of sufficient light that prevents it from reaching its full potential. I can't figure out where you set up the shot, and hence can't really offer too many suggestions about improving the lighting, but could you shine a flashlight, or something similar just on the frog, so everything else would still be black? Just a thought, because this really could be a winner.
Ioana
...and here I thought Rod was just making fun of my 500 watt light. lol I'm not having much luck with this topic.....but will continue my efforts. Thanks for the comments!