I wrote a report in college about the use of zebrafish in research studies. Also worked with them briefly at NIH for the same facility shown in the video. Zebrafish make up less than 1% of lab animals in use at any given time, but contribute valuable research to embryonic development and birth defects. Xenopus (African clawed) frogs are also used, but on a very small scale.
And who knew they'd turn out to be the cool glofish that we all love.