The Clarion Angelfish, Holacanthus clarionensis, is listed as Vulnerable on The IUCN Red List of Threatened Species™. This fish is found around the Revillagigedo Islands in Mexico, including Clarion Island, and inhabits rocky reefs with clear water.
The frequency and duration of El Niño Southern Oscillation (ENSO) events in the region of the Eastern Tropical Pacific appears to be increasing, and may threaten the Clarion Angelfish because ENSO events can result in waters that are too warm and nutrient poor for this fish for extended periods of time. In addition, the restricted distribution of this species and shallow water habitat may make it particularly vulnerable to oceanographic environmental changes due to climate change. The Clarion Angelfish has been collected for the pet trade in the past, but this is not currently considered to be a major threat.
The Clarion Angelfish is almost entirely limited to the Revillagigedo Islands Marine Protected Area and the collection of this species is prohibited in Mexican waters. However, given its restricted range and shallow reef-associated habitat it would benefit from receiving careful monitoring.