Started in 1889, the Bishop Museum Ichthyology collection is among the largest and most complete for the vast Indo-Pacific region. It contains over 40,000 cataloged lots, including over 3,000 type specimens. The primary emphasis of the collection is tropical coral-reef fishes within the Indo-Pacific, but it also includes material from pelagic and deep-sea environments. The collection includes a few freshwater fishes, mostly from rivers and streams in the Hawaiian Islands and elsewhere in Oceania.

In addition to specimen, the collection also houses over 20,000 large-format color images of prepared specimens and 35-mm in-situ underwater photographs. The collection is fully digitized, with complete and annotated records for all specimens entered in the database, and many of the film images scanned.

The fish collection represents the bulk of the lifetime work of Dr. John E. Randall, Senior Ichthyologist (now Emeritus), who began working in the collection in 1965 and a half-century later continues to publish on fish systematics and biogeography. Dr. Richard L. Pyle continues to add to the collection, with an emphasis on collecting specimens from deep coral-reef ecosystems (so-called “Mesophotic Coral Ecosystems”, or the Coral-Reef “Twilight Zone”), using advanced diving technology.