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The Bicolor or Oriole Dwarf Angel, Centropyge bicolor (Bloch 1787)


Bob Fenner

Centropyge bicolor (Bloch 1787), the Blue-and-Gold, Pacific Rock Beauty, Bicolor or Oriole Dwarf Angel. Here in N. Sulawesi

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

What used to be a "standard" in the pet-fish marine hobby, but often is too-damaged to recover, another Dwarf Angel of the genus Centropyge, the Bicolor or Oriole Dwarf Angel, can still be kept... given you know how, can secure an initially healthy specimen and "follow some basic rules" that are more or less universal for the genus... Good sized, well-established environment, lots of live rock with sufficient algae growth, a paucity of aggressive tankmates...

Zoogeography, Natural Habitat:

Found on shallow reefs (near the surface to about 80 feet) on scattered islands of the Indo-Pacific; the East African coast to Samoa and Phoenix Islands, to southern Japan, south to Noumea (New Caledonia), and throughout Micronesia. Live on broken/open reef areas, slopes usually in pairs or small groups.


    This species exhibits both inter (between) and intra (within) species aggression. Like most Dwarf Angels it is best introduced as the last fish... and if more than one is to be housed in the same system, the smaller ahead of the larger (by a few weeks).

    Bicolors can/do get along with most all reef denizens that get along with them... with the following provisos: That there is sufficient room for all. Please note, that though not generally considered "reef safe", all species of Centropyge are found... where? On reefs... Yes, they will at times nibble Tridacnid clam mantles, and may consume soft and even some stony coral polyp (slime mostly) material. However, given enough space, other foods, these fishes are indeed suitable for stocking with most all reef life. The other item is the general rule concerning animals not sharing a particular habitat niche. Dwarf Angels don't like to "share" their algae patch rocks... and there can be real trouble with similar sized Surgeonfishes, algae-eating Wrasses if space is at a premium.

    Reciprocally, large/r species of angels, including members of their own if too crowded... and "the usual suspects"... Puffers, Lions, Triggers, piscivorous Morays... will consume them given the chance.

Specimen Selection:

    This is by far the most important time you can/will spend in taking care of your fish... Take the time to investigate, be aware of what a clean, healthy specimen looks like, and more importantly, how it behaves:

1) Is the prospective purchase "bright", moving about, aware of your presence, its tankmates? Cyanided specimens, ones that have not received decent care in capture through your buying, may be "spaced out", having "private parties" in the corner of the tank... leave them.

2) Examine the fish's body with great scrutiny. Puncture marks (from decompression needling and other Angels' opercular spines mostly), reddened areas, raised or missing scales, fin spines torn down to their base... should disqualify a purchase.

3) Make sure the fish is feeding. Watch it carefully... is it moving about, nibbling at the bottom, rock? Good.

Centropyge bicolor (Bloch 1787), the Blue-and-Gold, Pacific Rock Beauty, Bicolor or Oriole Dwarf Angel (3), is highly variable in it's survivability in captivity. Some shipments are 100% live on arrival, others can be just the opposite within days. Better specimens come from other than the Philippines or Indonesia. To 6" if they live. This near full-size adult off Heron Island, GBR, Australia. Pix by Hiroyuki Tanaka and RMF.


A Bicolor at a wholesalers in Los Angeles... how they're generally and best maintained in the "string of custody" on their way to the end-user (that's you). Best to keep in such cubicles for their own and others protection, ease of re-capture, display to potential buyers.

Bigger PIX:
The images in this table are linked to large (desktop size) copies. Click on "framed" images to go to the larger size.


    Two aspects are critical in keeping Centropyge healthy and happy: Space and nooks/crannies... They need room to move about, darting in/out of holes, to feel safe, provide for forage surface area. Lots of healthy live rock, not too many busy fish tankmates. Seasoned systems over ones that are too new (months).

    How much space is enough? Sixty gallons is an absolute minimum IMO/E... with much more if you intend to keep other fishes, or more than one Centropyge.


    Mmm, besides being doomed to start with... from mis-handling, cyanide collection, not being fed in transit, overall stress... likely "poor environment" ranks second and lack of nutrition third as significant "reasons", sources of mortality for captive Centropyge bicolor. What do they eat in the wild? Algae mainly green filamentous algae and reds), crustaceans and worms. What will they eat for you in captivity? Pretty much the same... how can you best provide it/this? Not by flakes, pellets, sticks, frozen... but by having a goodly amount of live rock, and/or even better some of this and a good depth of substrate with plenty of infauna living, reproducing in it in a tied-in living sump, a refugium.

    Besides needed habitat, the live rock can/will present an ever-ready source of food organisms and forage opportunity. Hence, if you intend to house this or any other Centropyge species, it is STRONGLY recommended that you first procure, cure and culture your live rock a few months ahead of its/their introduction.

    So, you don't see yours feeding? It's not interested in those expensive foods you bought just for it? No worries. As long as the fish appears "full" it is likely doing just fine feeding on what there is in the system itself. If yours appears skinny, it is far more likely that this is due to bullying (observe your livestock carefully!) than a lack of food/feeding if there is a sufficient amount of live rock present.


    Centropyges are susceptible to the usual reef scourges (Crypt and Velvet), but more insidious and dominant as sources of mortality by far are injuries incurred during capture, handling, transport and care from the wild to your dealers. Again, the strongest urging on your part to thoroughly investigate how to discern the best specimens, carefully select one, and isolate/quarantine it before introduction to your main/display system.

    Quarantine as a concept is separate from the ideas of actual treatment. There may be no need to "medicate" or modify the environment (e.g. hyposalinity) a given animal. Simply placing in a darkish, secluded (from traffic) spot, allowing a new purchase to "rest up" and allow your observation for a few weeks may save you tremendous troubles... versus abruptly releasing it into your principal aquarium.

    A few pieces of live rock for food and shelter along with heating, and some filtration/aeration/circulation is likely all that is required.

    Some Centropyge angels are notably sensitive to copper medications... and some authors therefore proscribe the use of alternative therapies and therapeutic agents (e.g. formalin). If you use copper, I would make this a chelated format, with matching daily testing, and keep the therapeutic dose/concentration on the lower end (0.15-0.20 ppm of free cupric ion).


    The Bicolor has typical Centropyge reproductive behavior... living in small groups in a haremic fashion... With one dominant fish being the functional male, a few females and possibly some undifferentiated juveniles. The male spawning with the females in turn, cued by the environment (light, temperature, food availability...), the eggs being buoyant, floating to the surface. Young developing, in turn feeding on phyto- then zoo-plankters, being consumed as part of the plankton themselves... If "fortunate" being pushed along to available reef space, drifting down, converting to young...

    Male Bicolors are discernibly larger than females with a bit more vibrant color and perhaps a bit of orange on their flanks. Not to be too concerned re sexing however if it is your intention to try breeding this species. As with all Centropyge species, Orioles are synchronous protogynous hermaphrodites. They are "first females" that given room, need can/do develop in turn into functional females. If you have a large enough system, enough time going by, within a grouping one will become a male.

    This species as yet is not produced in commercial numbers (aquaculture), but all wild-collected. Though not endangered in its natural habitats, it is collected more and more from further/distal areas in the two countries of its principal collection (the Philippines and Indonesia).


    The genus Centropyge, comprising most of the Dwarf Angelfishes is a source of mixed blessings for the ornamental marine trade and the public it serves. On the one hand, this is a group of principally colorful, and always intelligent, playful reef species... on the other, they often present hardiness and feeding issues to uninitiated or aquarists unwilling to meet their needs. The principal issues in keeping the Bicolor are mirrored by its congeners. The need for space, hiding room, a dearth of "noise" from fish tankmates, plentiful algal and other infaunal invertebrate food organisms.

In Fiji

In Queensland, Australia

Off Heron Island, Australia

Verticals (Full/Cover Page Sizes Available

Bibliography/Further Reading:


FishBase: http://fishbase.sinica.edu.tw/Summary/speciesSummary.php?ID=5454&genusname=Centropyge&speciesname=bicolor

Allen, Gerald R. 1985 (3d ed.). Butterfly and Angelfishes of the World, v. 2. Aquarium Systems, OH. 352 pp.

Allen, Gerald, Roger Steene & Mark Allen. 1998. A Guide to Angelfishes & Butterflyfishes. Tropical Reef Research/Odyssey Publishing, Singapore/San Diego. 250pp.

Burgess, Warren E., Herbert R. Axelrod & Raymond E. Hunziker. 1990. Atlas of Aquarium Fishes Reference Book, v.2, Marine Fishes. T.F.H. Publications, Inc. NJ. 768pp.

Campbell, Douglas G. 1983. Marines: their care and keeping; Centropyge: pts. 1,2. FAMA 3,4/83.

Debelius, Helmut & Hans A. Baensch. 1994. Marine Atlas, v.1. MERGUS, Germany. 1215pp.

Emmens, C.W. 1985. Smaller Pacific angelfishes. TFH 6/85.

Fenner, Robert M. 1998. The Conscientious Marine Aquarist. Microcosm, VT. 432pp.

Fenner, Robert. 1998. Perfect little angels (Centropyge). TFH 4/98.

Hemdal, Jay. 1989. Marine angelfish; color and style. AFM 8/89.

Kuhling, D. Undated. Centropyge, dwarf angelfish who must eat their greens! Aquarium Digest International #38.

Kuiter, Rudie H. & Helmut Debelius. 1994. Southeast Asia Tropical Fish Guide. Tetra-Press, VA. 321pp.

Michael, Scott W. Fishes for the marine aquarium; pts. 16 &17: Pygmy angelfishes- diminutive, but beautiful; Some possible pygmy angels for your marine tank. AFM 1,2/96.

Moenich, David R. 1987. Angel food; the most important single factor in keeping marine angels healthy is a varied diet. TFH 6/87.

Moenich, David R. 1988. Pygmy angelfishes: the genus Centropyge. TFH 1/88.

Nelson, Joseph S. 1994. Fishes of the World. John Wiley & Sons, NY. 600pp.

Steene, Roger C. 1985 (2d. ed.). Butterfly and Angelfishes of the World, v.1. (Australia). Aquarium Systems, OH. 144pp.

Stratton, Richard F. 1989. The bicolor angel. TFH 2/89.

Taylor, Edward C. 1983. Marine angelfishes- thinking small. TFH 5/83.

Thresher, R.E. 1984. Reproduction in reef fishes, pt. 3; Angelfishes (Pomacanthidae). TFH 12/84.

Wrobel, David. 1988. Dwarf angels of the genus Centropyge. SeaScope Spr. 88.

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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