Dr. Michael Tobler in the OSU Zoology department has just been awarded a $481,000 grant from the National Science Foundation to study the evolution of fishes in extreme environments. Hydrogen sulfide is a highly toxic gas that is lethal for most animals, even at low concentrations. In southern Mexico, small livebearing fish have independently colonized multiple sulfidic springs, where hydrogen sulfide naturally occurs in high concentrations. These fish provide an opportunity to study how vertebrates have managed to survive in conditions that are lethal for most other organisms. Adaptation in sulfide springs also leads to reproductive isolation between sulfidic and non-sulfidic ecotypes, providing insights about how new species evolve. Understanding organisms’ responses to naturally occurring stressful environments can ultimately be used to better understand causes and consequences of organismal responses to human altered environments. The project fosters collaboration in research and education between scientists and students from the United States and Mexico. The project also establishes a public outreach platform for fish biologists to interact with fish hobbyist organizations as a means to disseminate research findings to the lay public.