Black & White Heniochus Butterflyfish

The Black & White Heniochus Butterflyfish, Heniochus acuminatus, also known as the Longfin Bannerfish or Pennant Coralfish, is an elegant saltwater fish recognized by its dramatic black-and-white banding and exceptionally long, flowing dorsal filament. Bright yellow coloration across the tail and rear fins adds vivid contrast, while the tall, laterally compressed body creates the graceful silhouette that often draws comparisons to the Moorish Idol.

Native to a broad Indo-Pacific range extending from East Africa and the Persian Gulf through the Maldives, Southeast Asia, Japan, Australia, Micronesia, and French Polynesia, this species inhabits protected lagoons, channels, and outer reef slopes. Juveniles are often encountered alone, while adults commonly occur in pairs and spend much of their time cruising near reef structure in search of plankton and small invertebrate foods.

Reaching approximately 10 inches as an adult, the Black & White Heniochus is an active but generally peaceful marine aquarium fish that can make an impressive centerpiece in a spacious fish-only or fish-only-with-live-rock aquarium. It is typically adaptable once established and feeding well, but its tendency to investigate corals and other sessile invertebrates prevents it from being considered reliably reef safe.

Quick Care Guide

Care Level: Easy to Moderate
Minimum Tank Size: 125 gallons
Temperament: Peaceful
Diet: Omnivore / Planktivore
Reef Safe: No
Region: Indo-Pacific
Scientific Name: Heniochus acuminatus

Tank Requirements

Provide a spacious marine aquarium with a combination of open swimming room and substantial rockwork. Caves, overhangs, and sheltered areas allow the fish to retreat when desired, while broad open sections accommodate its active cruising behavior and long dorsal filament.

Because adults can approach 10 inches and have a tall body profile, generous horizontal swimming space is important. Avoid overly dense aquascaping or narrow passages that could restrict movement or repeatedly contact the elongated dorsal fin.

Moderate to strong water movement, excellent oxygenation, efficient filtration, and stable water quality are recommended. Established live rock provides additional browsing opportunities and can help newly introduced specimens settle more comfortably.

A secure aquarium cover is advisable, particularly during acclimation when sudden movements may occur if the fish becomes startled.

Diet and Feeding

The Black & White Heniochus naturally feeds heavily on zooplankton along with small benthic invertebrates and other edible material found around reef habitats. Juveniles may also occasionally clean parasites from larger fish.

In captivity, offer a varied selection of mysis shrimp, enriched brine shrimp, finely chopped shrimp, clam, mussel, krill, and quality frozen marine blends. Plankton-based preparations and frozen foods designed for butterflyfish are excellent additions.

High-quality marine pellets and omnivore preparations can also be offered once the fish is accepting prepared foods consistently. A varied diet is preferable to relying heavily on a single food source.

Feed two to three smaller meals per day when practical, particularly for newly acclimated specimens that benefit from frequent feeding opportunities.

Temperament and Tankmates

The Black & White Heniochus Butterflyfish is generally peaceful toward unrelated marine fish and can coexist successfully with many community species. Suitable tankmates include tangs, rabbitfish, peaceful wrasses, clownfish, larger gobies, and appropriately compatible angelfish.

Adults naturally occur in pairs, and this species can sometimes be maintained with additional Heniochus in sufficiently large aquariums. However, adequate swimming room and careful observation are important, particularly when introducing multiple specimens.

Avoid highly aggressive tankmates that may damage the long dorsal filament or repeatedly prevent the butterflyfish from feeding. Very territorial species should be introduced with caution.

Reef Compatibility

The Black & White Heniochus Butterflyfish is not considered reliably reef safe. Although plankton forms an important part of its natural diet, individuals may also pick at coral polyps and other sessile reef organisms.

Soft corals, stony corals, zoanthids, tubeworms, and other exposed invertebrates may be investigated or nipped. Individual behavior varies, but frequent feeding does not guarantee that a specimen will leave corals untouched.

For predictable long-term care, this species is best maintained in a fish-only or fish-only-with-live-rock aquarium rather than a reef display where protecting corals and sessile invertebrates is a priority.

Water Parameters

Temperature: 75–80°F
Specific Gravity: 1.024–1.026
pH: 8.1–8.4
Alkalinity: 8–12 dKH

Stable salinity, excellent oxygenation, and consistently good water quality are more important than maintaining an exact value within these ranges.

Common Considerations

• Large, tall-bodied fish: Adults can approach 10 inches and require generous swimming room for long-term housing.

• Long dorsal filament: Provide open pathways and avoid overly restrictive rockwork that may damage the extended dorsal fin.

• Not reliably reef safe: Corals and other sessile invertebrates may be nipped or consumed.

• Frequent varied feeding: Multiple small meals of planktonic and marine-based foods help maintain good body condition.

• Similar-species identification: Heniochus acuminatus closely resembles the Schooling Bannerfish, Heniochus diphreutes, but the two species differ in body proportions, behavior, and reef compatibility.