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Of the eight species of marine angels of the genus Holacanthus, likely the most commonly offered in the pet fish trade is the Atlantic Rock Beauty, H. tricolor. There are many positive traits, characteristics going for this species. It's beautifully colored and marked, intelligent, of a gorgeous, graceful body and fin conformation. And as a bonus to collectors, cost to hobbyists, it can be found and collected in good numbers in its wide range in the tropical West Atlantic. The one real downside of its captive care is the Rock Beauty's dismal history of survival in captivity. Easily half are lost within a month of capture in the wild.
There are reasons for the low survival of this species in captivity, mostly having to do with a lack of ready, acceptable food, along with the usual vicissitudes of collection, holding, shipping trauma. My intent here is to grant you insights about the wild-environment of this species in an effort to either forestall your haplessly trying this difficult angel (steering you to more hardy ones), or provide you with useful information on how to provide for its captive husbandry.
The Rock Beauty Angelfish (family Pomacanthidae) is a member of the genus Holacanthus ("grooved spine"; "tricolor" for the yellow, black and blue eye-highlights) which includes eight described species, four each in the tropical Atlantic and Pacific. Other aquarium species of this genus are the Passer, Clarion, Queen, Blue, and on rare occasion Holacanthus limbaughi. H. africanus is a rarity in the West. The Bandit Angel, H. arcuatus, a Hawaiian endemic is unfortunately offered in the trade quite regularly. It rarely lives for any period of time.
Tropical western Atlantic; Georgia , Bermuda, the northern Gulf of Mexico to Rio de Janeiro, Brazil.
To about eight inches total length in captivity, recorded to fourteen in the wild.
As with the childhood tale of "Goldilocks & the Three Bears", most wild-caught wildlife has a "too small", "too large", and "just right" range of sizes that are best to select for. Too little specimens take too much of a beating in being caught, held, not-fed (typically) and transport through supply channels to "end users" like aquarists. Too big ones are too often lost for most of these same reasons, plus their steadfastness to wild diets, adapting poorly to conditions of confinement. The "just right" size range for the Atlantic Rock Beauty is somewhere in the 3-4 inch or so range (overall length).
This is one of those species of marines that small tears in fins, blemishes on the body, fin bases can spell real TROUBLE. Examine prospective purchases very carefully. Damaged ones very often "go down hill" very quickly. Look to the animals behavior as well as indicative of its internal and mental-emotional health. Buyable specimens are bright, alert, with clear eyes, erect fins, moving about, aware of your presence.
You hope... though this isn't a probability with most imported individuals (they generally don't readily feed at first in captivity), it is a very good sign that the one you have your eyes on is accepting or at least curious re offered foods.
Time On Hand:
The Atlantic Rock Beauty is part of the minority of livestock choices that should not be "left at the dealers" for a grace/rest period. In the vast majority of cases, delaying, leaving the specimen at the dealers will only lengthen its starvation period, subject it to more stress, weaken its immunity.
If you have done your homework, set-up a system to suit its needs, do be diligent about its acquisition. Order, otherwise have your LFS contact you when they receive their shipment, go there, observe the new arrival/s and pick up your specimen. Similarly I don't encourage a quarantine period for this species. The trauma, continued loss of health from very probable non-feeding is not worth the trade-off in communicable disease prevention.
Larger (a fifty five is a minimum for a too-small individual, a hundred gallons for a three-four inch one) is better for this species, as is wider. A stockier shaped system is better suited to allow rock work, other decor and non moving invertebrate livestock for their use. Being able to "get away" is important as is having nooks, caves to sleep in at night.
Vigorous life on well-established live rock is mandatory. Macro-algae that hails from the region (http://wetwebmedia.com/maralgae.htm)
Rock Beauty's appreciate NSW conditions. Near Sea Water... Clean water that is well-aerated, filtered of natural specific gravity (near 1.025, they do not like artificially low spg.), pH (8.2-8.4), alkalinity etc. Detectable levels of ammonia, nitrite, and very little nitrate are likely not to be a problem in such a system described. Higher dissolved organic concentrations can/do lead directly to loss of vigor, loss period.
Temperature is best in the mid to upper seventies F. Once again, in a larger system it should be easy to maintain a steady thermal regime. As always, using two or more smaller wattage heaters rather than a single large one is good insurance against varying temperature.
Yes, they're touchier than the average marine.
Properly placing a Rock Beauty is simple... stipulated that its environment has been set up properly, aged for a few months. With dimmed lights, and the light off in the tank, either a drip method or occasional addition of water from the system technique can be used. Leave the aquarium lights off for another day so your Rock Beauty can "learn" the placement of objects in the system.
If other species of fishes are going to be sharing the tank, it's best that they're placed in order of smaller, very easygoing first, larger last, after your Rock Beauty.
Territoriality/Predator Prey Relations, Other...:
This is a quintessential shy, retiring species, that under the best of circumstances can be expected to hide a good period of the time. It's easily over-stressed by crowding, or placement with aggressive species. Ideally your Rock Beauty will be catered to, made the center of attention of your/its system, at the zenith, co-placed with other western Atlantic species of an easygoing nature. Triggers, other Angels, including more than one Rock Beauty should be avoided.
This species is known to be a synchrononous protogynous hermaphrodite, individuals becoming females first, then possibly males with growth, age. The breeding harems involve one male, a few to several females over a wide-ranging area (a few hundred square yards).
This is the single largest aspect of this species husbandry that accounts for their dismal historic aquarium survival. Rock Beauties need to be placed in a system that is chock a block with the sorts of living materials they pick on all day in the wild: preponderantly sponges, then some algae, Zoanthids and sea squirts. Where can you come up with these food items? Grow them in/on your live rock. Yes, this will take a good size system... hundreds of gallons for an adult specimen, and is best done with "native" Floridian, Caribbean live rock... or wild-cultured from the area. Alternatively and to supplement what you can grow, there are human-intended algae, sponge and Ascidian materials that can be found at your oriental grocers, or section in a large-size metropolitan food store.
Though they're not part of the same ecological niches or possibly even ocean, bivalves can come to be relished by Rock Beauties. Split clams, mussels, even oysters out of a jar can be tried, used. Take care not to overfeed "outside offered" foods.
If you were to examine the beak-like mouth parts, sharp outer teeth, crushing bones in the mouth... and the digestive tract of the Rock Beauty you would realize it is a browsing species. This species feeds continuously during the day time, small bits at a time.
A good general practice is to apply a vitamin and iodide preparation to the system on a weekly basis, and on the fish's foods a good fifteen minutes ahead of offering.
Disease, Prevention, Diagnosis, Control
Rock Beauties are of two polarized classes. Apparently healthy and doing fine, or quickly dying/dead. If yours should start showing signs of joining the latter group, a cut, scrape... it is likely necessary to move it to a separate treatment system (where it will likely not accept much in the way of foods), check the main/display system for what is amiss (likely water quality), remedy this, and try to treat the fish in the separate treatment facility.
Wholesalers and hobbyists have had good results dealing with "breakdown contagions" (red, bloody marks, sores, general malaise) with this species using Furan compounds (typically Nitrofurazone). Full dose, added aeration, water and chemical treatment re-application daily are called for. I and others have had less success with antibiotics like tetracycline, erythromycin.
Not able or willing to provide an appropriate size, live-rock stocked system for a Holacanthus tricolor? Look to a less-demanding centerpiece/species of the genus Holacanthus then. Perhaps a less-demanding Queen, or Blue if you want something from the tropical Atlantic... or a King/Passer from the eastern Pacific. Or perhaps another genus of Pomacanthids or not an Angelfish at all. I am aware that there are instances in which folks have kept this species in "fish only" set-ups, fed it "nothing but prepared foods and lettuce" and "it's done fine". These are exceptions, rare ones.
The Atlantic Rock Beauty is not easy to accommodate, but well-worth the effort. For its care, health, a biotopic shallow tropical west Atlantic presentation/set-up is best. Provide a large biotopic setting, maintain it properly, and culture this animal's living foodstuffs and you will be richly rewarded.
Bellomy, Mildred D. 1975. Rock Beauty. Marine Aquarist 6:7, 75.
Campbell, Douglas. Marines: their care and keeping, Holacanthus-Apolemichthys, parts 1 & 2. FAMA 3,4/81.
Fenner, Robert 1998. The Conscientious Marine Aquarist. 432 pp. Microcosm, VT.
McKenna, Scott. 1988. Keeping the rock beauty angel. TFH 7/88.
Michael, Scott W. 1997. Holacanthus angelfish. Their behavior isn't very angelic. AFM 10/97.
Moenich, David R. 1989. Marine angelfish: genera: Holacanthus. FAMA 11/89.
Moenich, David R. 1990. Marine angelfish: Holacanthus. AFM 8/90.
Phillips, Merry Elisabeth. 1993. A special angel (H. tricolor). TFH