The size of parrotfishes of this genus ranges from the rather small-sized
S. radians with a known maximum length of to the large
S. viride, which reaches lengths of up to . Members of this genus are
sequential hermaphrodites, starting as females (known as the initial phase) and then changing to males (the terminal phase). However, some males are direct-developing, and these usually resemble the initial phase. These direct-developing terminal-phase males often display different mating strategies. In most species, the terminal phase is more colourful than the initial, but a notable exception to this rule is
S. cretense. They use their
pectoral fins to move; the
caudal fin is reserved for rapid bursts of speed. The genus
Sparisoma is fairly successful, but populations have been falling somewhat because of
overfishing and other human activities. However, as mentioned above, it is the main grazer of algae. Still, since populations have been falling, the coral reefs may be at risk, because too much
algae is deleterious or harmful to
coral. ==Species==