[1] Chaetodontoplus septentrionalis is commonest on rocky reefs which have large boulders and stones, as well as rubble slopes.

Small juveniles are frequently commoner at depths over 15 metres (49 ft) down to 30 metres (98 ft) they are found on rocky, patch reefs and frequently stay close to a crevice where they can shelter if required.

[3] Like all other angelfish it is a protogynous hermaphrodite, with all individuals being female initially and the dominant ones changing to males.

[6] Chaetodontoplus septentrionalis was first formally described in 1844 by Coenraad Jacob Temminck and Hermann Schlegel with the type locality given as Nagasaki.

[7] The specific name means northern, thought to be a reference to its more northerly distribution than apparently related species.