Some fish are desirable for their rich personality. Others are sought for their intense coloration.
Particularly amongst reef aquarists, some are valued solely for their grace. And there is hardly a
reef-dwelling animal more graceful than the lyretail angelfishes (Genicanthus spp.). The lyretail
angels, from the common Lamarck’s angel to the “holy grail” masked angel, have always held
the interest of newbie and veteran marine aquarists alike. Even so, as it just recently has been
released from commercial production for the first time, the swallowtail angel (G. melanospilos)
will most certainly be getting a lot of well-deserved attention throughout the hobby.
Swallowtail Angel: Like no other
Absolutely, the swallowtail angel (sometimes called the black spot or blackbreasted angel) is a
beauty. And it possesses plenty of personality, thank you. But when it comes to poise and
elegance, this fish (even compared to many other genicanthid angels) is supereminent. In the
proper setting–a large marine or reef tank with generous open swimming area–it is
unforgettable. Even if that is at all overstating this fish’s natural beauty, it is entirely safe to say
that pictures cannot do it any justice.
A feature of the species that most immediately stands out to fishkeepers is its shape. It is
deeply compressed laterally as are most of its family members. But it is considerably curvier
than other angels. Luscious curves indeed… Its well-rounded head, shoulder and belly taper
towards its anterior like a fiery comet. Both the dorsal and anal fins terminate in rather sharp
points. The tail is yet more impressive, longer and more lyre-shaped than that of the fish’s
As in other members of the genus, this fish exhibits a high degree of sexual dimorphism. Both
male and female swallowtail angels are exceptionally attractive. Females have a metallic baby
blue base color that is richest in the face and fades gradually towards the hind. A thin, bright
blue lines runs along the margins of her dorsal and anal fin. A vivid yellow sheen fills in the rest
of the dorsal fin, fading like a golden mist into her midsection. The top and bottom of her white
tail is heavily edged in black. Males share the blue background and edging; and, that is pretty
much where the similarities of coloration end. An orange line fringes the blue edging of the
dorsal and anal fins, breaking into widely dispersed spots before reaching his body. Dark, thin,
vertical bands run across the entire flank and forehead. The edging on his tail is much fainter
than the female’s, fading to silvery grey in-between and bearing orange speckles that emerge
from the bands over the caudal region. Long, silvery filaments extend from the tips of his tail
Still, there’s much more to a swallowtail angelfish’s panache than its body shape and markings.
There is something in the way it moves… The manner in which is so deliberately dashes over
the aquascape is mesmerizing. Particularly around feeding time, it effortlessly dances circles
around its tankmates as it meticulously snatches tiny morsels from the water column. If you
believe that open waters are a waste of tank space, this fish will prove you wrong and then
At around seven inches length upon reaching full size, the swallowtail angel is actually a bit
smaller than the average angelfish. Still, given its activity level, it requires a bit more swimming
space. Thus, an aquarium volume of 125 gallons or more is recommended (some suggest
providing an even larger tank). Open aquascapes are preferable to aquascapes that are filled to
the rim with rock. A full lid should be in place to prevent fatal jumps.
This fish is not an especially finicky eater. Its main fare should be meaty. Larger pieces of prawn,
mussel, etc. should be chopped down to a manageable bite size. Fully adjusted specimens will
likely accept flakes and small pellets. That being said, the swallowtail angel is a zooplanktivore
that will very much enjoy and benefit from the inclusion of live zooplankton in its diet. For this,
live copepods, amphipods and brine shrimp are entirely suitable.
Swallowtail angels seldom present compatibility issues. They (along with the other
genicanthids) are easily the most reef-safe among the angelfishes, very rarely if ever taking a
nip at a coral, clam, etc. They generally get along pretty well with other fish. They may not,
however, get along with their own kind. This is especially so with males. In many cases a single
male can be successfully maintained with a single female or small harem. Small groups of
females can also be kept, though some aggressive contests may take place. There is a rather
interesting reason for this.
In the absence of a male, a dominant female will transform into a male. This means full color
change and all. The change is irreversible. This might be an exciting development for a
monetarily minded aquarist, being as the purchase price of males exceeds that of females by a
factor of 2-3x.
With a lifespan of 10-15 years, the stunning Swallowtail Angel can provide its keeper with an enormous
amount of satisfaction.