Pterois volitans is a tropical marine fish which usually occurs in waters with temperatures of between 22°C and 28°C. Lower temperature ranges have been observed in the USA (14°C to 24°C) (Meister et al. 2005). The depth range of this species is 10 to 175 meters (Schofield & Fuller 2006). The red lionfish favours coral reefs and rocky outcrops (DaCosta-Cottam et al. 2009), although it has been observed over coral patches, near sandy bottoms and in mangrove, seagrass and even canal habitats (Schofield 2009; González et al. 2009). It is also found in lagoons and harbours (FishBase 2006). It hides in unexposed places during the daytime often with its head down, practically immobile.
Richter (2009) hypothesises that the range of the lionfish will reach the Gulf of Mexico and expand south along the eastern coast of South America until it reaches a southern latitude where it cannot tolerate low temperatures (Hare and Whitfield 2003, in Richter 2009). The southernmost sighting has been in Columbia, though there is potential for the lionfish to extend past that (Schofield 2009, in Richter 2009). The northern limit of the range is North Carolina; a functional expansion northward is unlikely unless the lionfish population undergoes a rapid evolution to thermal tolerance; some juveniles have been seen as far north as Long Island Sound, although they cannot become established due to cold winters (Richter 2009). Temperature is a possible factor limiting; the mean chronic lethal minimum is 10°C and the mean temperature of feeding cessation is 16°C, indicating that the lionfish might over-winter on the southeast United States continental shelf, with a northern limit of Cape Hatteras (Kimball et al. 2004).