Emperors are a family of around 30 different species, sometimes also called emperor breams. Features common to this family include thick lips, strong jaws, and cheeks without scales. Emperors live on or close to coral reefs and are found only in coastal tropical waters.
Emperors are bottom-feeding fish that eat sea snails, crabs, sea urchins, worms and many other animals that live on the seafloor. Some of the larger species feed on other fish. Some species have molar-like teeth which they use to crunch the shells of their food.
Most species of emperors begin life as females and change sex to become males as they grow. Large schools of spawning emperors can form around the new or full moon in some months. Females release thousands of eggs which are then fertilised by sperm released by males and will drift in the plankton until hatched and big enough to return to the reef.
The redfin emperor bream has a mainly silvery body colour, with a large, dark reddish patch starting above the eyes and running along the back to the end of the dorsal fin.
There are four vertical white stripes which are about the same width as 2 scales. The tail is yellowish/orangish. When the pectoral fin is opened, it reveals a strong dark reddish patch.
This species can grow to 60 cm, but is usually observed much smaller than this, typically 15 - 25 cm.
This species can be confused with the bigeye seabream (Monotaxis grandoculis) which is also a member of the emperor family. The main difference between the two species is the width of the four vertical stripes - in Monotaxis grandoculis the stripes are four scale-widths wide. In Monotaxis grandoculis the dark patch on the back does not extend down toward the middle as much as in this species (Monotaxis heterodon).