The juveniles are brownish with large, discrete creamy white blotches on the body these develop brown spotting as the fish matures.

The adults are solitary fish, living in the vicinity of and sheltering beneath ledges or caves during the day.

It is a carnivorous species which preys on benthic invertebrates such as crustaceans and molluscs, as well as fishes, which it forages for during the night.

[4] Plectorhinchus chaetodonoides was first formally described in 1801 by the French naturalist Bernard Germain de Lacépède with no type locality given but it is likely to have been somewhere in modern Indonesia.

[5] The specific name chaetodonoides means having the form of Chaetodon which when Lacépède described this species referred to both butterflyfishes and marine angelfishes and is an allusion to the serrated operculum, similar to that of marine angelfish, and the then presumption of a close taxonomic relationship between this species and the genus Chaetodon.