Increased atmospheric carbon dioxide (CO2) has led to increased levels of dissolved CO2 in the Earth’s oceans. This has generally decreased the pH of – or “acidified” – ocean water. Decreased pH, along with other chemical changes ultimately caused by an increase in dissolved CO2, could have direct effects on the physiology and behavior of fishes. Physiology deals with the systems contained in a living organism that allow it to function and respond to its environment. Scientists have dedicated a lot of time and effort to studying the potential effects of OA on fish physiology and behavior. This publication will summarize the current state of our understanding on the topic, with special emphasis on Florida fishes. It will also address current knowledge gaps and limitations inherent in understanding the real-world effects of a complex global process using data largely collected on isolated fish in laboratory experiments.