Metastasis is the cause of 90% of cancer-related mortality yet it remains incompletely understood. Studying the events at the metastatic site in particular is difficult as most sites of metastasis are not amenable to imaging as they occur deep inside the animal. I took advantage of a strain of zebrafish that is transparent (owing to the genetic deletion of two classes of pigmentation cells) which allowed me to image these cells an hour after injection. I took this image to study what happens to tumor cells at the metastatic site.