Schooling bannerfish (Heniochus diphreutes) care guide

Group
Marine fish
Other names
False Moorish idol, Poor man's Moorish idol, Pennant bannerfish
Family
Chaetodontidae (butterflyfishes)
Origin
Indo-Pacific from East Africa and the Red Sea to Hawaii, Japan and the Kermadecs; outer reef slopes and channels at 5–30 m (to 210 m).
Water
saltwater
Maximum size
21 cm
Temperature
24–27°C
pH
8.1–8.4
Hardness
Salinity SG 1.023–1.026
Minimum tank
500 litres
Care level
intermediate
Temperament
peaceful
Reef safe
no

Care

A shoaling fish best kept in a small group, so it needs a long tank with open water; 500 litres for a small group is an estimate. Water figures given here are general marine aquarium guidance, not species-specific: 24–27 °C, pH 8.1–8.4 and a specific gravity of 1.023–1.026. Keep nitrate low and water quality stable. It lives in large groups in the wild, and juveniles (and sometimes adults) act as cleaners. White with two black bands, a yellow tail and a long white dorsal pennant, it is often sold as an easier substitute for the Moorish idol. It is not to be confused with the very similar H. acuminatus, which is more solitary. The IUCN lists it as Least Concern with no major threats. Sources: Wikipedia, List of marine aquarium fish species (en.wikipedia.org/wiki/Listofmarineaquariumfishspecies); Wikipedia (en.wikipedia.org/wiki/Heniochusdiphreutes). Checked October 2026.

Diet

Feeds on zooplankton in open water. In the aquarium it takes mysis, brine shrimp, krill and quality flake or pellets readily; feed small amounts several times a day.

Breeding

An egg-layer that pairs to spawn. Not bred in home aquaria.

Compatibility and tank mates

Peaceful and does well in a group with other peaceful to semi-aggressive fish. Listed as not reef safe, as it may pick at corals and other invertebrates.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.

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