News / Species Spotlight / Clarion Angelfish (Holacanthus clarionensis) (09/05/18)

Clarion Angelfish (Holacanthus clarionensis)

Species Spotlight - Clarion Angelfish (Holacanthus clarionensis)
Aquarists have been describing certain species as holy grails for as long as theyve been keeping fishes in little glass boxes, and high on this illustrious list is Mexicos visually stunning and exceedingly rare Clarion Angelfish.

Holacanthus clarionensis is a case study in how a small, geographically restricted population can become dramatically different in appearance. The species was described more than a century ago from the Revillagigedo Islands, situated roughly 240 miles southwest of the Baja Peninsula. Its at this small volcanic archipelago, roughly in the middle of nowhere in the Eastern Pacific Ocean, that a bright orange angelfish came into existence.

The Clarion Angelfish ultimately shares a common ancestor with the Eastern Pacifics widespread Passer or King Angelfish (H. passer), which differs in being predominantly colored a dark shade of blue, along with having pointed dorsal and anal fins (versus rounded). Youll find the Passer as a dominant species throughout the Gulf of California, south as far as Peru, and westwards to the Galapagos Islands, but it is largely replaced at the other oceanic islands in this region.

Also relevant to this discussion is the legendary Clipperton Angelfish (H. limbaughi), a species which has seemingly never been kept in captivity and which is known only from Clipperton Atoll, located some 500+ miles south of where we find the Clarion. Here we see a very different direction that the ancestral Passer stock has taken, keeping the blue coloration of the body, but losing most of the white vertical bar and the yellow coloration of the fins. But as different as the adults of these three species look, their evolutionary closeness can be seen with the many similarities shared in their juvenile colorations.

Recent molecular study has suggested that both H. limbaughi and H. clarionensis began speciating roughly 1.4 million years ago, presumably in response to changes in sea level and ocean currents in the region. But, despite their obvious dissimilarities and a million plus years of isolation from one another, the Clarion and Passer Angelfishes are still VERY closely related and have been reported to hybridize in the wild. H. passer is now present in small numbers at the Revillagigedo Islands, and H. clarionensis can be encountered on rare occasion outside its home archipelago (where roughly 99% of the total population for this species is thought to reside). Its been spotted at Cabo San Lucas, northwards to the submerged Alijos Rocks and at Guadalupe Island, and even along continental Mexico, near Puerto Vallarta. But these arent considered permanent populations, merely vagrants brought to these distant shores by the prevailing currents.

In the wild, juveniles of these three Holacanthus are seen to act as cleaners of larger reef creatures, and adults have been noted to pick parasites from Hammerhead Sharks and Manta Rays. Unlike most of the larger angelfishes, these species frequently form large roving shoals that descend upon rocky substrates to pick algae and benthic organisms like sponges and tunicates. This same sort of behavior can be seen among some of the tangs and surgeonfishes with a similar diet, and is likely a shared adaptation for avoiding the aggressive and territorial Stegastes damselfishes. But in captivity, a wide variety of foods are accepted, making these some of the easiest and hardiest pomacanthids to keep.

In recent years, the Revillagigedo Islands have become off-limits to collectors, and thus the Clarion Angelfish is back to being one of the most difficult to (legally) obtain. After an absence of a couple years, Quality Marine is once again able to offer aquacultured specimens, making this otherwise unobtainable orange beauty available for those with the space and means to keep one of the planets most beautiful marine fishes.

Last week, Quality Marine received a hand full of aquaculture specimens after not having any since 2016. Increasing the number of cultured species we offer to our customers is an integral part of making the aquarium trade more sustainable.