For fish, water quality is similar in the way air quality affects humans. "The water is what the fish breathe, so it needs to be as health for them as air is for us," Thomas said. New fish tend to stay in quarantine for 30 to 60 days. "Anytime you bring new fish in or change a routine in any way it can have negative or positive affects on the water quality," Thomas said. "Even just gong from one tank to another, they have to get use to new tank mates, they have to get use to new water quality, they have to get use to a new environment, it causes stressors whether you want it to or not."