Coal miners used to carry canaries with them down into the mines as a sort of warning device of bad air quality. Because canaries are so much smaller than humans, they would die from breathing the toxic air way before the miners were in any danger. That served as inspiration for artist “Marei Wollesrsberger”:http://marei.co.uk/ whose “BioSafe Habitat”:http://www.we-make-money-not-art.com/archives/009608.php concept involves aquatic plants or fish serving the canaries sacrificial function. In reading about the project, I discovered a fascinating (and patented) species of fish called “GloFish”:http://en.wikipedia.org/wiki/GloFish. These modified zebrafish literally glow when exposed to water contaminants. They’re also the only genetically modified organism to be legally sold as a pet.