Ask the WWM Crew
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Do you think that fishes are intelligent? I believe some are; at least to the point of knowing of their own existence. Others are pretty autistic; freshwater Siamese fighting fish (Bettas), will chase their own tail around endlessly.
Still, there are some fishes that are demonstrably capable of learning, and remembering. The "highest" Order of fishes (Tetraodontiformes), including the Triggerfishes, Filefishes, and Puffer groups are very smart indeed; using tools, visual and audible communication, and possessing a rich repertoire of social behaviors.
The case for piscine intelligence could be made for the marine angelfishes as well. They almost always become the "boss" of a system; recognizing their aquarist feeders. As a an added bonus to fish-keepers, many are strikingly beautiful as well.
Classification: Taxonomy, Relation With Other Groups
The family Pomacanthidae contains nine genera with seventy four (and growing) species. These fishes bear a stout spine on the gill cover (Pom = "cover", acanthus= "spine") liable to get tangled in nets, poke livestock and you. This is often stated as an easy distinguishing mark between them and the closely related Butterflyfishes.
Natural and Introduced Range:
Circum-tropical; prominent species in shallows to a few hundred feet on rocky and coral reefs worldwide. Most are found in the western Pacific, with only nine species in the Atlantic and four in the eastern Pacific.
From a few inches to a couple of feet. I have heartbrokenly seen piles of foot and a half Pomacanthus angels on docks in Singapore and Thailand, on their way for human consumption.
Captive Suitability Scoring:
After long thought, investigation of others declared opinions, and handling thousands of these fishes over the last thirty some years in the trade I've come up with the following scheme of "scores" for each on its likelihood of surviving the rigors of aquarium care. To a degree this information is necessarily historical (what has happened, may not be the general trend to come), and is subject to "improvement" on the keepers side as a consequence of providing larger, more stable quarters and more diligent husbandry. But, by and large a relative score of one (1) indicates the "highest and best" survivability under captive conditions; let's say most of the specimens of this species collected surviving more than three months. A score of two (2) is indicative of a mortality of more than fifty percent between one and three months. Lastly, and sufficient for our purposes, a three (3) is the worst score, with more than 50% of the species perishing before a months time of capture. I entreat you to leave the latter group to the sea, or at least to study and provide the best possible circumstances for these animals.
I'm aware that other authors, even highly respected scientists? ratings are different than your dealers and mine probably consider my "judgments" too harsh. My advice is indeed, not to rely on what's stated here and/or any one other source of information. Before purchasing these (or other livestock) do your best to gather as much pertinent "accurate, significant, and meaningful" information as you can from reading, other hobbyists and the industry.
The Genera and Principal Aquarium Species: Click on the Link for Coverage by Genus
Selection: General to Specific
Size: Very generally; for small species get one that is 2-3 inches in length, the genera of larger angels, about 3-5 inches. Smaller individuals tend to be too beaten up in the processes of collection and transport and too-big one's adapt poorly, refusing food and displaying unwanted behaviors.
Reddening: Bloody color around the mouth, fins or body flanks is definitely a bad sign. I would not consider such a specimen for purchase. The scales should be flat, smooth and clean on the body.
Mental/Emotional Problems & the Possibility of Poisoning: Look at the prospective purchase; is it looking back at you? It should. Psychologically damaged and poisoned (cyanide is not a drug) specimens may look 'perfect' color and body-wise; but are generally lethargic. You can even touch them without their moving. Don't even think about buying such a specimen. healthy angels are vigorous, aware animals that require skilled two-net capturing techniques.
Eating: Is it? Ask to see; more than once. Cyanided fishes will not, do not eat, or if they do, almost invariably die in a very short while following. Once off feed due to non-feeding, collection practices... angelfishes rarely resume.
Collecting Your Own
Involves knowing and applying as much knowledge of angel behavior and locomotion as you can. Almost all angels are wild-captured by a two hand-net technique. Driving a specimen out with one net (or a poker) into one covering the most likely exit point. You must be deft, and smart.
Angelfishes require careful decompression, either through passing time gingerly "needling" them one at a time.
Habitat: With such socially aggressive and interactive species as angels are with their tankmates; having as large a system as possible with as much cover/decor as practical can't be emphasized enough. The larger species need big volumes just for themselves; but all angels will beat the dickens out of other livestock if too cramped or not provided with plenty of cover.
Angelfishes, especially the larger species should only be put into a seasoned, previously stocked system. The reasons for this are two-fold. One, they prefer those water conditions, and secondly, to preclude the angel developing a this-whole-tank-is-mine attitude.
For the various species, a more constant temperature in the mid seventies to low eighties covers all ranges. Nitrates aren't critical, but pH is a good indication of overall water quality; 8.0-8.4 is ideal.
Make it vigorous and heavy on aeration. Systems with angels benefit in many ways by having high flow levels; angelfish seem to relish playing in the flow and bubbles, therefore cutting back on a lot of other "anomalous mis-behavior" they get into (like chasing and bothering other livestock). Also, these fishes are active, and need the oxygen and sped up filtration.
In the wild angels are either found individually or in "mated" pairs; very rarely in continuous close group associations (except for spawning times for some species). Such behavior probably is a manifestation of resource partitioning. Most species will fight with members of their own species, likely with other's of the same genus, and quite possibly with other similar-appearing fishes of about the same size. The only safe approach to mixing them is to provide plenty of space, cover, and observe them carefully.
In almost all cases it is best to have one member of an angelfish genus per system; ideally only one angel period.
As regards other-than-angel species, most disputes are nominal, as long as the angel(s) are left ultimately "in charge".
This is a critical moment in the life of your angels. Usually you can tell right away whether a specimen will "make it" in it's new surroundings or that you'll have to "pull it".
Turn the lighting way down, and lightly feed the tank if there are other livestock (their should be). Carefully place the new specimen (that's been dipped or quarantined) floating in a transparent container into the system. This allows the angel and existing occupants to get a look at each other without being able to do anything else. Add an airstone if necessary, so the individual can visually acclimate for a good twenty minutes. Only then should you release it, and not unless you have a good hour to watch the angel from there.
Large predators, like sharks, sea lions and humans eat adult-size angels in the wild. Juveniles are eaten by everything that can fit them in their mouth.
Reproduction, Sexual Differentiation/Growing Your Own:
Angels are separate sexes, though some (Centropyge, Genicanthus) are protogynic synchronous hermaphrodites (first females turning into functional males). Spawning, either in pairs or in "harems" is environmentally cued by light, temperature, other organism's activities. Gametes released into the water column, result in some planktonic larvae; developing and settling at the whim of currents.
Some species have been tank "bred" utilizing hormonal manipulation. Young have been tank reared for Pomacanthus, Centropyge and Genicanthus species. See Thresher for details.
The smaller hermaphroditic species display a varying degree of sexual differences in color and structure. Males are typically slightly larger, more colorful with longer more trailing unpaired fins.
Genera of larger angels are largely indistinguishable sexually; some having males with "head bumps", and varying spiny-ness.
Types, Frequency, Amount, Wastes
Foods and feeding is the key area where angels are kept successfully and not. Many are largely coral, sponge and/or algal grazers, that will fare poorly unless these foods or substitutes are quickly employed. Feeding strikes with these animals should not be ignored for even short periods of time.
An open fresh or live clam, mussel or shrimp may stop your angel from "giving up the ghost", and going to fish heaven.
Angels should be fed a minimum of once daily, preferably twice. I prefer to offer meaty foods (chopped shrimp, crab, clam...) in the morning so I can remove it before retiring later; and a vegetable-based prepared mix in the later afternoon.
As a lead in to the next topic, I'll mention a nutritional "disease", Vitamin A blindness, problematical in angels that do not receive enough green material in their diets. Campbell suggests that at least fifty percent of angel diets be comprised of greenery. Natural algae, spinach and home-made preparations are encouraged.
Infectious, Parasitic, Nutritional, Genetic, Social
Angelfishes are frequently imported with gill and body parasites; particularly flukes and the Protozoans Cryptocaryon, Amyloodinium and Benedenia. If properly cared for before you receive them, there is little you have to do other than standard prophylaxis (quarantine, dipping) to prevent spreading or intensification of infection.
If you find your angels are breathing hard, unable to close their gill covers, I would check water chemistry and adjust first, followed by moving the individuals to a treatment tank for copper and possibly antibiotic treatment.
The group is more susceptible to head and lateral line erosion (HLLE) than most fishes. Good water quality, adequate feeding with vitamin C enriched foods tend to keep this in check.
Another not-uncommon malady of angels is the viral Lymphocystis clumps of lumpy white/gray matter at the base of fins. This is best ignored as it is usually self-curing. Some writers have endorsed the use of biological cleaners and physical removal. I would wait a month or two before possibly doing damage.
If you read other's accounts (you should) of which are good, okay, and lousy marine angel species, you'll quickly find there is no end of differences of opinions. Be aware that what's enclosed here, of a necessity, are vast generalizations concerning animals that are individualistic. You may get an "impossible" species to eat out of your hand; or an "easy-care" variety might possibly succumb from nothing on the way home from the shop.
Most "articles" and "books" in this field are authored and edited by folks who have limited exposure to the "real-world" of aquaristics. Many of them are scientific types who have large, complicated facilities that hobbyist's won't. Some writers are successful collectors and intermediary dealers who don't know fact one about keeping an end-user system and livestock for more than a week. The last group I'll mention are the most numerous; hobbyists, divers and retail workers who "think they've seen it all" by having a brush with a few specimens.
They, and my opinions should be taken with a "bag of salt", not a grain. Before plunking down your hard-earned cash, investigate through reading and talking with people who have adequate, first-hand experience.
There are no other families of fishes with as many show specimens, looks and behavior as the marine angels. By choosing a healthy specimen, of the good species, and feeding it properly you will have a center-piece organism for years.
Angels in General
Allen, Gerald, Roger Steene & Mark Allen. 1998. A Guide to Angelfishes & Butterflyfishes. Tropical Reef Research/Odyssey Publishing, Singapore/San Diego. 250pp.
Allen, Gerald R. 1979. Butterfly and Angelfishes of the World, vol.2. Mergus Publishers, W. Germany.
Baensch, Hans & Helmut Debelius. 1994. Marine Atlas, v.1. MERGUS, Germany. 1215pp.
Burgess, Warren E. 1991. Two new genera of angelfishes, family Pomacanthidae. TFH 3/91.
Emmens, C.W. Pacific angelfish. Marine Aquarist 3(1):72.
Emmens, C.W. 1983. Large Pacific angelfishes. TFH 3/83.
Gonzalez, Deane. 1980. Angels of Hawaii. FAMA 7/80.
Hemdal, Jay. 1989. Marine angelfish; color and style. AFM 8/89.
Ladiges et al. 1978. Marine fish, angelfish. Aquarium Digest International #19.
Lobel, Phil S. 1975. Hawaiian angelfishes. Marine Aquarist 6(4):75.
Michael, Scott W. 2001. Touched by and Angel (fish). AFM 7/01.
Miller, Gary. 1985. Angelfish of the Caribbean. FAMA 8/85.
Moenich, David R. 1987. Angel Food; the most important single factor in keeping marine angels is a varied diet. TFH 6/87.
Moenich, David R. 1988. Breaking the rules (marine angel compatibility). TFH 3/88.
Steene, Roger C. 1977. Butterfly and Angelfishes of the World, vol.1. Australia. Mergus Publishers. W. Germany.
Stratton, Richard F. 1994. Practical angels. TFH 10/94.
Thresher, R.E. 1984. Reproduction in reef fishes, part 3; Angelfishes (Pomacanthidae). TFH 12/84.
Toyama, Dean. 1988. The angelfish(es) of Midway Island. FAMA 11/88.
Tuskes, Paul M. 1980. Observation on tropical Atlantic
angelfish on the reef and in captivity. FAMA 5/80.