Heniochus Black and White Butterfly (Heniochus Acuminatus)

Also Known As: Longfin Bannerfish, Pennant Butterflyfish

Compatibility and Behavior
The Heniochus (Heniochus acuminatus) is the butterfly that flies a banner. A long, flowing dorsal filament trails like a pennant behind a tall, disk-shaped body dressed in bold black and white vertical bands, set off by soft yellow on the tail and dorsal edge. Because these fish are proportionally taller than they are long, even a small one carries a commanding presence as it glides through the mid-water. It's also worth noting the Heniochus is frequently offered as a hardier, more forgiving entry into the butterfly world than the true Chaetodon species, which is a fair part of its appeal. Temperament tends to be peaceful toward dissimilar tankmates, settling in nicely with calm tangs, Anthias, and wrasses when introduced with some thought, though it may get mildly territorial toward other butterflies or similarly shaped fish in smaller or sparse tanks. If you have a bigger system, you can try multiple Heniochus Butterflies, introduced simultaneously to reduce chances of aggression. As with the family generally, treat it as reef safe with caution: it can nip soft corals, LPS, zoanthids, and clam mantles while foraging, so it's a stronger fit for a FOWLR or a carefully planned reef than a prized mixed system.

Aquarium Requirements
This is a fish built for height, so it rewards a tall tank with long footprints, generous viewing panes, and open water to show off that banner. Tiny and small individuals from 1 to 2 inches make a practical start in a 75 to 90 gallon tank, while the larger size classes are better suited to 100-plus gallon systems with strong, stable filtration. Give it plenty of rockwork for grazing and shelter along with clear sightlines and moderate, well-oxygenated flow so it can cruise comfortably. Keep it well conditioned on a varied diet of mysis, finely chopped seafood, quality marine pellets, and frozen preparations, which both maintains its condition and takes away much of its motivation to over-sample corals in a mixed setup.

Specifications
Approximate Size: T: 1", Sm: 1.5–2", SMd: 1.5–2.5", Md: 2.5–3.5", Lg: 3.5–4" (Heniochus are taller than they are long)
Diet: Omnivore; mysis, chopped seafood, plus quality marine pellets and frozen blends
Origin: Indo-Pacific
Care Level: Intermediate
Reef Safe: With caution
Temperament: Peaceful to semi-aggressive
Minimum Tank Size: 75 gallons for small specimens, with a larger system required as it grows
Special Considerations: Reef safe with caution, as it may nip soft corals, LPS, zoanthids, and clam mantles, so best in a FOWLR or coral-cautious setup; can be territorial toward other butterflyfish and similarly shaped fish