Not furry, but we like them anyway.

Heniochus Butterflyfish

Heniochus diphreutes

Also called Schooling bannerfish, False moorish idol, Pennant butterflyfish

SpeciesShort profile

From Indo-Pacific: Red Sea and South Africa east to Indonesia, Japan, Australia and Hawaii, though missing from much of Oceania1

At a glance the quick version

Length18 to 21 cm1 2 3

Sizemedium

Elegant trailing dorsal banner

Can be kept in a group

Easy to care for

Looks how to spot one

Tall, compressed butterflyfish with a long dorsal banner

A white body crossed by two wide black diagonal bands, with yellow fins toward the back. A very long white filament trails from the dorsal fin like a pennant, and a dark band links the eyes across the head.2 3

Colourswhiteblackyellow3 2

Personality what they are like

Peaceful and sociable. In the wild it gathers in large schools above the reef.3 1 2

Daily activity how busy a day looks

A mid-water swimmer that needs open swimming room, as wild fish feed on plankton in open water.1 2

Grooming and care the hands-on bits

Rated easy care. Several can be kept together if they are added at the same time. Generally safe in a reef tank when well fed, but watch it around corals.3

Home where they are happiest

A tank of at least 125 US gallons (about 475 L). Saltwater at 22 to 26 °C (72 to 78 °F), pH 8.1 to 8.4, specific gravity 1.020 to 1.025. Wild fish favour outer reef slopes and current channels, mostly at 5 to 30 m.3 1 2

Food basics what goes in the bowl

A plankton eater. Wild fish pick zooplankton from the water column, so offer small meaty marine foods such as mysis and similar frozen preparations.1 2 3

Company who they like around

A schooling species that does well in a group. Adults form pairs when breeding.1 2 3

The story where it all began

David Starr Jordan described the species in 1903. In the aquarium trade it is often sold as a lower-cost look-alike of the Moorish idol.1 2

Fun facts for the dinner table

1
Young fish act as cleaners, picking parasites off other fish.1
2
Divers near the Maldives have seen it cleaning a sunfish.2
3
It has been recorded as deep as 210 m.1
4
It is often called the false moorish idol because of its similar shape and banner fin.2

Recognised by the official bits

IUCN Red List: Least Concern (assessed 2009)1

The care rhythm Furry Diary remembers it for you

A typical home-care rhythm for a Heniochus Butterflyfish. It is our own starting plan, not a vet's advice, and you can change every line in the app.

FeedingSmall amounts once or twice a dayevery day
Temperature checkevery day
Salinity checkevery week
Top-upTop up evaporation with fresh RO water, not salt waterevery day
Water testevery week
Water changeAbout 10 to 20% of the waterevery 2 weeks
Glass cleanevery week

Start a free diary

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Where this comes from

Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at [email protected] and we will fix it.

FishBase: Heniochus diphreutes, False moorish idol fishbase.seused for distribution, length, depth, habitat, diet, cleaning behaviour, IUCN status, describer
Wikipedia: Heniochus diphreutes en.wikipedia.orgused for colour description, length, schooling, cleaning, aquarium trade note
LiveAquaria: Schooling Bannerfish liveaquaria.comused for aquarium care, tank size, water parameters, temperament, diet, colours

Checked 2026-09-30. Text is written in our own words from these sources.