Chaetodon kleinii is a laterally compressed butterflyfish that reaches roughly 6 inches as an adult. The body ranges from yellowish brown to orange, broken by a dark eye bar and dark snout, pale vertical bands, and fine pale to bluish spotting. Coloration and banding vary considerably by locality, and the mark above the eye develops into a bright blue accent in mature specimens. The species is widely distributed across the Indo-Pacific, from the Red Sea and East Africa to Hawaii, Samoa, southern Japan, eastern Australia, and New Caledonia, with a separate population in the Galapagos. In the wild it favors deeper lagoons, channels, and seaward reef slopes at depths of about 4 to 61 meters.

Plan on a long, spacious marine system for an adult. Published minimum volumes vary from 50 to 100 gallons, and 75 gallons serves as the practical baseline, though larger footprints offer better swimming and retreat space. Furnish the tank with abundant established live rock for browsing, secure crevices, and visual barriers, while leaving broad stretches of open water for cruising. Efficient filtration, strong oxygenation, and moderate flow with calmer resting pockets suit this fish well, and stable reef-quality parameters should be maintained throughout.

A mature system carrying algae film and microorganisms on the rockwork helps new arrivals settle and graze naturally during acclimation. This butterflyfish is not considered a habitual jumper, but it can leap when startled, so a secure lid or mesh cover is a sensible precaution.