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Pomacanthus
imperator (Emperor Angelfish)
Certainly
one of the most beautiful marine angelfishes, but one with a
mixed record of longevity, the emperor, Pomacanthus
imperator is well-deserving of it's majestic
name.
Most
individuals are lost due to poor capture technique, transport,
acclimation and lack of nutrition. In this article I will
detail the most common symptomology for avoiding a doomed
specimen, and offer my insights into the species appropriate
care.
Juveniles
are similarly marked as Koran (P.
semicirculatus) and several other large related angels,
with series of concentric dark blue, black and white rings.
Considered individuals should be well colored and marked with
no apparent traumas.
However
the primary selection character/criteria I would describe as
"brightness"; that is an active/searching interest
in it's immediate environment. Prospective specimens should be
curious, reactive to your presence, not so much dashing about
their enclosure, nor totally "spaced-out" but aware,
following motion, light and anything else near them.
For
most hobbyists I strongly encourage the trial of individuals
only starting between 10-14 cm. size. These seem best suited
for beginning life in captive conditions. Larger one's have
more difficulty adapting to aquariums and smaller one's don't
accept prepared foods as well. There are, of course,
exceptions, but this is my rule of thumb guideline.
Roger
Steene, good buddy of Gerald Allen, offers his opinion that P.
imperator "is a sturdy aquarium species". This
is so for speciemens hailing from Australia, the Indian Ocean
and Red Sea; but not for most of the Indo-Pacific. Only
individuals that appear full-bodied, alert as described above,
and heartily accepting several foodstuffs should be
considered. Be especially wary of overly-brightly-colored
disoriented specimens from the Philippines and Indonesia. Many
of these I've found to be cyanided and doomed. I consider the
species not as easy to maintain as the koran P.
semicirculatus, but certainly hardier than those in the
genera Euxiphipops and
Pygoplites
Similarly avoid rapid
breathers; more than eighty gill movements a minute's too
many.
One
last note re selection: Take care in capturing and
transporting members due to their gill cover (opercular)
spines. These are often easily fouled, torn by nets, leading
to subsequent infection. I advise net-less directing the
intended specimen into a suitably double or otherwise
puncture-insulated bag or at worse lifting ultimately by hand.
Be Careful! The family name is derived from the Greek roots
"pom" = cover and "acanthus" = thorn, for
good reason.
Environmental:
Conditions
Habitat Imperators
are found exclusively associated with coral reefs in the wild,
in shallow to one hundred feet depths.
Chemical/Physical Good water quality
must be optimized and constant. use a good quality salt mix,
at a 1.022-1.025 specific gravity and maintain pH in the
higher range, 8.2-8.4. A protein skimmer is a must.
Angels are sensitive
to "new tank syndromes". Place them in systems that
have been seasoned for a few months.
Filtration
Very important to the
group of angelfishes is vigorous circulation and removal of
metabolites.
Display
Even
in captivity emperors seek out/prefer the comfort of shelter
from boulders, caves and coral niches. They will do well only
where offered the possibility of retreat.
Size of aquaria? The
bigger the better. I would not even start an emperor in a
system of less than four hundred liters. Ultimately, you will
need one twice plus this size.
Behavior:
Territoriality
Emperor
angels are considered amongst the larger members of their
family, able to reach some forty centimeters. Like most
species in their and related genera, they do best kept singly
and not with other angel species of a similar size.
Introduction/Acclimation
Place
in a non-occupied or re-disturbed system in subdued lighting
and leave some indirect light on for a day. Make favored foods
available a few times a day at first.
Predator/Prey Relations May
be readily eaten by typical predaceous types. Beware of Billy
Grouper, Eli the Eel, Larry the Langusto and Porky-boy the
Puffer...
Reproduction:
Lifelong
pairing/mating seems to be the rule. The family are egg-scatterers,
clued from tide, temperature and light stimuli. Some authors
cite sex-change capacity and harem/lek activity. I doubt it.
Feeding/Foods/Nutrition:
Types, Frequency, Amount, Wastes
Similar
to members of the genus Holacanthus,
emperors and other Pomacanthus
are known consumers of a large amount of sponge (phylum
Porifera) material, then algae, other animal material and
vascular plants in the wild. Will you go broke buying live
sponges or specialty frozen foods made of the same? Nah. In
captivity they can/usually will adapt/adopt to prepared
frozen, fresh and dry foods.
Disease: Infectious, Parasitic
All
specimens are suspect. Most have been impaired/traumatized by
handling and weakened by handling to the extent that
invariably-present protozoan infections (and possibly internal
and external parasite fauna) may gain an upper hand (fin?).
All newcomers should be preventively dipped and otherwise
quarantined for a good two weeks. Trust me.
If
yours appears to be sick, look first and foremost to water
quality, next to feeding/nutrition, and last chemical
therapeutic treatment. Be careful about interrupting
biological conversion with copper compounds, though they are
the treatment of choice for the two common scourges Cryptocaryoniasis and Amyloodiniumiasis
(Oodiniumiasis). For
general or non-specific malaise I would recommend a massive
water change, vitamin application and a few grams of fruit
sugar (fructose).
Close:
I
like and agree with Hans Baensch, the man behind Tetra's
advice as regards this and other angels; try other easier
marines first and learn the value of culturing the algae genus
Caulerpa or other
suitable bio-assay species as viable indicators of water
quality, before plunking down the big bongo bucks for
something like an emperor angel.
With
the permission of Robert (Bob) Fenner webmaster of WetWebMedia
(bobfenner@aol.com) |
