Regal angels are found ranging widely over rich coral areas, ducking in and out of crevices. These sheltering caverns are always places of good circulation.
Water quality. I acknowledge Hemdal with pointing out that angels be introduced to established systems only. They do not weather nitrogen cycling changes well. Wait till the aquarium has been set up a good three to four months before introducing angels. Gunther Dawal in Prof. Ladiges Aquarium Digest International piece credits strong water circulation and frequent water changes with his success with Pygoplites.
Tank size should be at least four feet in length, sixty-plus gallons for even a small regal. They attain a length of about a foot in captivity, two in the wild.
An important factor in failure and success in keeping angels. I recommend at least once daily an offering of a meaty food; chopped fresh or frozen clam, crab, shrimp, squid... and some source of greenery. Marine algae are best; you can grow some of these, others can be purchased from the oriental section at your food store. Lettuce made mushy by freezing, spinach, husked peas are used by some. Some personal acquaintances that have had success keeping Regals on more standard fare advise avoiding gelatin-based frozen foods. There are excellent preparations made without gelatin and these are much better for your angels. Check the labels for ingredients.
Live rock and dry-prepared foods are accepted often, but should not be considered staples. Live saltwater foods are unnecessary for marine angels and too easily introduce disease. Stick with frozen.
Refusing food for a few days should not overly concern you; however large angels do have hearty appetites. Feeding strikes cal for water changes, vitamin-based feeding stimulants and a switch-up in foods offered. A fresh opened shellfish often works wonders. Your specimens ought to have an overall plump appearance when in good condition. San Francisco Bay Brands are excellent.
Our most problematic area with regal angels is nutrition. Pygoplites feeds almost exclusively on tunicates (sea squirts) and sponges in the wild. Allen and Steene (1979) give this species their most difficult species rating for the amount of care required.
The locale of source is a very important matter. Currently most regal angels are still imported from the Philippine Islands. These are the worst. I will not elaborate here as I've covered the "reasons why" elsewhere (irresponsible methods of capture, holding, transport...). I lived and worked in the trade in the P.I. for two years; the fish used to be better.
Thankfully these fish have a very wide range, being found in some numbers throughout the Indo-Pacific and Red Sea, and are offered from other countries. If you're determined to "buy and try" the best places to procure a Pygoplites from is every place else: The Red Sea is the absolute best; Sri Lanka, Australia and Singapore are also favored. They are found as far east as some of the islands of French Polynesia (the photo here was taken in Moorea), but not from Hawaii. Ask your dealers the origins of their stock; if they don't know of refuse to warrant where from, let that outfit fail. They don't deserve to be in the trade.
Considering size, whenever you buy this or any other large angel shoot for a mature individual, three to four inches overall length with adult coloration.
Eating and Index of Fitness (Plumpness): In remarking on his experiments with Australian angels, Emmens stated "It would seem that not more than one in ten specimens of Pygoplites diacanthus survives for any period and the majority seem to be condemned to slow starvation in the aquarist's tank." The specimen must be shown to be feeding in the supplier's tank and be full-bodied, especially not "thin in the head". If at all practical, leave the prospective purchase with a deposit for a week or two and visit back for another feeding demonstration.
Frayed fins and rapid breathing (more than one-hundred shallow gill beats per minute) are also cited as reasons for leaving a regal where it is.
The quality of "brightness", otherwise described as interest and reaction to changes in it's environment seems difficult to describe. Is the Angel "looking around"? Does it respond to your presence? Good.
Most of what's known is recounted by Thresher (1984). Many angels are protogynous hermaphrodites, changing from functional females to males through socially controlled phenomena much as do several of the wrasses. Some angels live in harems, others form monogamous pairs, still others as periodic bachelor(ette)s.
During spawning seasons at dusk of the dark or night they release floating eggs and sperm into the upper water column after an elaborate spiraling dance.
Centropyge, Genicanthus & Pomacanthus have reports on spawning in captivity. Experimental stripping of the latter has produced limited numbers of tank-raised young. & Pomacanthus have reports on spawning in captivity. Experimental stripping of the latter has produced limited numbers of tank-raised young.
Only advanced aquarists with large tanks should attempt to keep P. diacanthus providing adequate habitat and daily animal and plant food matter.
When enough dealers lose money for lack of demand for this most beautiful of angelfish species, Regals will be left in the oceans where they belong. With so many other attractive, hardy marine angels available they should be. See it in a video or book, take up diving and go enjoy regal angels in their natural surroundings. Please don't buy this fish unless you're prepared.
Allen, Gerald R. & Roger C. Steene, 1979. Butterfly and Angelfishes of the World. Aquarium Systems/Mergus Publishers, Germany.
Allen, Gerald, Roger Steene & Mark Allen. 1998. A Guide to Angelfishes & Butterflyfishes. Tropical Reef Research/Odyssey Publishing, Singapore/San Diego. 250pp.
Burgess, Warren E., 1991. Two New Genera of Angelfishes, Family Pomacanthidae. Tropical Fish Hobbyist. 3/91.
Emmens, C.W., 1972. Pacific Angelfish. Marine Aquarist. 3(1):72.
Emmens, C.W., 1983. Large Pacific Angelfishes. Tropical Fish Hobbyist. 3/83.
Hemdal, Jay, 1989. Marine Angelfish; Color & Style. Aquarium Fish Magazine. 8/89.
Ladiges, Prof., 1978. Marine Fish: Angelfish. Aquarium Digest International #19.
Moenich, David R., 1988. Breaking the Rules. Tropical Fish Hobbyist. 3/88.
Thresher, R.E., 1984. Reproduction in Reef Fishes. Pt. 3 Angelfishes (Pomacanthidae). Tropical Fish Hobbyist. 12/84.