Most snapper mature between 3 and 5 years of age or around 230 mm in length. Adult snapper can grow to 1 m in length (over 15 kg) and live to over 60 years in age.

Adult snapper are generalists, capable of occupying a wide range of habitats and eating a large variety of food sources. They prey predominantly on crustaceans, but they also eat shellfish, sea urchins and other fish.

We can further divide adult snapper on the basis of behaviour; some snapper remain within very small areas (a few hundred meters) that contain structurally complex habitats such as rocky reef; other snapper move over hundreds of kilometres annually. Some of these larger scale movements are likely to be connected to spawning (but not all spawning snapper undertake large movements).

Fishing has a major influence on adult snapper. This influence includes direct extraction as well as the mortality of snapper that interact with fishing gears but are not landed, the impact of fishing gears on seabed habitats important to snapper, and fishery selectivity that modifies the size/age distribution of snapper that are not caught .

Adult snapper are important predators, and the influence they have on their food sources can even modify the structure of the environment they live in. This has been demonstrated in marine reserves where the recovery of snapper and other predators resulted in an increase in kelp forests after these predators reduced populations of kelp-eating urchins.

The abundance of snapper in an area also influences their growth rates: when there are more snapper, their growth slows as they compete for food.