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Related FAQs: Clarion Angelfish, Marine Angelfishes In General, Angelfish ID, Selection, Behavior, Compatibility, Systems, Health, Feeding, Disease,  

Related Articles: Holacanthus Angels, Marine Angelfishes

/A Diversity of Aquatic Life

The Clarion Angel, Holacanthus clarionensis Gilbert, 1890

Bob Fenner

Four inch aquarium specimen

Angelfishes for  Marine Aquariums
Diversity, Selection & Care
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by Robert (Bob) Fenner


A juvenile and adult Clarion Angel in Mexico's waters at Socorro Island in the Islas Revilligigedos.

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Unfortunately, another expensive angel due to it's isolation and related costs for collection and transport, the clarion angel is perhaps the hardiest, most undemanding species of marine angelfishes.

It's brassy coloration and behavior belie nothing not true concerning Holacanthus clarionensis. They're bold, beautiful and behaviorally comical.

Classification: Taxonomy, Relation With Other Groups

Clarions are members of the marine angelfish family Pomacanthidae, presently divided into seven genera. The genus Holacanthus ("grooved spine") includes eight described species, four each in the tropical Atlantic and Pacific.

Natural Range

Tropical East Pacific, limited, specific range, some volcanic islands of/in south western Baja California, the Islas Revillagigedos. These I consider Roca Partida, Islas Socorro & San Benedicto, a sea mount "Hurricane", and of course the other volcanic spire-namesake Isla Clarion itself. I have espied this fish in small numbers around Cabo San Lucas at the southernmost

tip of Baja, around the Cortez corner up to Cabo Pulmo. It has supposedly been found all the way down to Cocos in Costa Rica and southwestward to Clipperton. Shallow to one hundred or so feet.

Selection: General to Specific

This is a model species in the way of uncanny good health and behavioral adaptability. There is one "dark side" I'd like to bring up; an issue of capture/transport "challenge". When/where specimens have met with enough insult, in particular wide, fast, extended thermal stress, they may appear fine, but be doomed. Hear me out on this, I have seen tangible results of the same. If, in the long haul from their native haunts, steady heat goes awry, sufficient long-term physiological damage may be done. Once again, my admonition against buying new arrivals. If need be, put a deposit down, otherwise wait a good two weeks...

Environmental: Conditions


The larger the better and with plenty O' nooks and crannies. I've kept tiny to a couple of inch species in smallish aquaria; the giganto systems are much easier to keep stable and maintain. A good rule of thumb is ten gallons per one inch of angel.


I concur with Moenich re the necessity for clean, toxin-free water for angels; we depart company on the item of specific gravity. It's my opinion that more success is met with relatively higher (for aquariums) densities, 1.022 to 1.025. This subject needs far more elucidation than we shall deal with here. It is a common practice in the trade and hobby to "scrimp", utilizing less artificial salt mix to control/limit cost, increase gas solubility and concurrent stocking/carrying capacity, and dis-favor parasitic and infectious disease-causing organisms, but at what physiological cost to the "desired" inhabitants? Many species as a group and individuals on the basis of their physical condition are mal-affected by abnormal high, low or changeable saltiness/density. Intertidal specimens, as you might surmise are more tolerant compared to deeper water types. Species whose life-habits are tied more closely to less-than broad, read that euryhaline, conditions will not do well under similar regimens as their symbionts. By the by, narrow-salt tolerant situations are termed stenohaline, just in case Hollywood Squares comes back on.

Anyway, my point is to keep your hydrometer reading high and constant for these and other deeper water species that are closely allied with invertebrate fauna.

Behavior: Territoriality

Compatibility is much as other large marine angels. Clarions enjoy being the alpha fish of the system, will fight with their own kind and other angels of similar size. One note regarding this species that bears mentioning: other than incidental damage from opercular and fin spine altercations, purposely (over)crowding clarions does not result in outright, overt agonistic behavior or noticeable agitation/stress to the individuals involved. Of a necessity, our commercial ventures have required temporary (days to a few weeks) of high density. Allen's photo on p 293. illustrates that this is not a totally unnatural event either.


Should not be the first or only specimen. A few damsels as dither fish are recommended. Make easy, fast adjustment to established, stable systems.

Predator/Prey Relations

Clarions have no real/significant known predators. They are considered a variety of "Batesian mimic", enjoying the impunity of another species due to their warm color and brash/bold behavior. They have as far as I could find, not been recorded in the stomach contents analyses for sharks, tunas and other possible munchers.

They will themselves pick at and try to ingest most everything in their environment, being intensely and eternally curious. Large crustaceans may eat them as they rest on the bottom at night (this is how we collect them in quantity), so choose their tankmates carefully. Sedentary creatures like urchins and sea-fans are fine as long as they are not edible or toxic.

Reproduction, Sexual Differentiation:

I've observed spawning in the Spring and Fall in the Islas Revillagigedos volcanic group. Groups amass and in pairs, adults rise to the surface and release their sex cells. Females appear larger, rounder and slightly less intensely orange.

Feeding/Foods/Nutrition: Types, Frequency, Amount, Wastes

Moenich mentions the use of fresh and frozen (without embellishments like salt, butter, et al.) peas for vegetable source enhancement. I'll throw in my usual directions to the oriental foods section, department, or specialty outlet for algae and other "greens" prep.s. Of course, clarions will gladly gobble algae available to them in their systems. Do yourself and your livestock a favor and leave out nutritional placebos like various lettuces. These have no practical food value.

With foods continuously available, your Holacanthus should appear robust to rotund, they do in the wild. Make convenient some foodstuff for a good part of the day that your specimen can mack and snack on at it's leisure; shellfish and gelatin-emulsified "formula" foods are especially good for this. And a note concerning purposely provided sponge-containing material/food. This is not merely a good idea, for this genus it is absolutely imperative to their color and general health. Somewhere down the line I will provide you a release of some work I synthesized from others' on this exact issue in relation to another species, one of the two California damselfishes, the garibaldi Hypsypops rubicunda. In fact, let's do that next.

For now, let me tickle your intellectual fancy with the statement that both these species are known "sponge-culturists" and that co-enzymes in they're poriferan fields are responsible for their brilliant, intense coloration.

Disease: Infectious, Parasitic, Nutritional, Genetic, Social

Campbell mentions the need for sufficient dietary vegetable material to prevent blindness due to Vitamin A deficiency. He rightly suggests greens make up fifty percent plus of foods offered.

Torn, severely punctured and generally thrashed specimens I've had good luck treating with fresh water dips heavily laden with "furan" compounds, especially Nitrofurazone. Broad-spectrum, gram negative antibiotics blended into food as follow-up have apparently helped.


After collecting and distributing thousands of clarions over several years and never failing to have them acclimate quickly and completely to aquarium conditions, I am of the considerable opinion that this is an ideal captive species. Should you inherit or win the lottery, consider them.

Bibliography/Further Reading:

Allen, Gerald R. 1978. Butterfly and Angelfishes of the World. Vol 2. Hans Baensch, W. Germany.

Campbell, Douglas. 1981. Marines: Their Care and Keeping, Holacanthus-Apolemichthys: Part One. FAMA 3/81.

Moenich, David R. 1990. Marine Angelfish: Holacanthus. Aquarium Fish Magazine, August 1990.

Weiss, Marc. 1986. The Cosmopolitan Clarion. T.F.H. 9/86.

Angelfishes for  Marine Aquariums
Diversity, Selection & Care
New eBook on Amazon: Available here
New Print Book on Create Space: Available here

by Robert (Bob) Fenner
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