http://www.livescience.com/php/multimedia/imagedisplay/img_display.php?s=animalworld&c=&l=on&pic=080206-seethru-fish-02.jpg&cap=Researchers%20created%20a%20see-through%20zebrafish%20so%20they%20can%20study%20disease%20processes,%20including%20the%20spread

Researchers created a see-through zebrafish so they can study disease processes, including the spread of cancer. Credit: Richard White/Children’s Hospital Boston