Adult great barracudas live in and around the edges of coral reefs. They tend to avoid brackish water unless they are getting ready to spawn (Paterson 2000). Post-larvae live on the margins and in the estuaries where they are protected. When they get large enough to protect themselves, they will move out into the open ocean and then to the margins of the coral reefs. These barracudas occur in clear water (Blaber 1997).
Great barracudas prefer water temperatures between 74F and 82F, although they have been found in much colder water (Paterson 2000).