Least Concern· population stable· assessed 2010

Longfin bannerfish

Heniochus acuminatus

Sighting evidence at Crystal Bay Nusa Penida, Bali

Photo: mualeyyy · CC BY-NC

Bannerfish at Crystal Bay act as cleaner fish for visiting sunfish, a facultative cleaning behaviour not commonly observed in this species elsewhere. The elongated dorsal fin that gives the fish its name is visible from several metres away and helps divers locate active cleaning stations before the sunfish are visible.

Evidence at this site

5 records within 25 km

Confidence: medium

Last confirmed Mar 2026

Seasonality

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

How is this calculated?

Sighting evidence is compiled from iNaturalist observation records within a set proximity radius, filtered for quality-grade observations. “Last confirmed” is the date of the most recent research-grade record. Record count covers a rolling 24-month window. Confidence reflects record count, recency, and consistency of seasonal signal.

Longfin bannerfish

Evidence at this site

Seasonality

Also seen at other sites