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Reprinted
with permission from:
Dr. Joanne Norton
Freshwater And Marine Aquarium
magazine
Leopard Angelfish
Photos and Text
by Dr. Joanne Norton
FAMA: February 1985, Vol. 8, #2
Angelfish color variation is very
interesting because the development of
some angelfish pigment patterns depend
not only upon the genetic makeup of
the fish but also on the photoperiod
under which the fish is kept during
the early months of its life. Under
continuous light, silver angelfish fry
develop no stripes (Norton, 1982c). A
zebra lace angelfish having two doses
of zebra and one dose of dark has
three black, vertical body stripes if
raised in a 14-hour day; if raised in
continuous light, fish with the same
genetic makeup have black spots (the
"cobra" pattern) instead of stripes
(Norton, 1982d). This article is about
another spotted pattern, called
"leopard" in the trade, which is
dependent on the proper photoperiod
during the early part of the fish's
life.
Figure 1: Leopard angelfish, when
purchased.
Figure 2: The fish in Figure 1, when
adult,
now with the smokey pattern.
I first saw leopard
angelfish in an aquarium shop in
March, 1981, and bought one. This fish
(Fig. 1) had much lighter
background color than the cobra
angelfish, but, like the cobra, it had
black spots on the body. However, as
this fish grew, he changed into a
smokey (Fig. 2), in which the
rear half of the body is mottled with
black. I tested this male for his
pigment pattern genes by crossing him
with a silver female. The offspring
all had the zebra pattern of three
black, vertical body stripes (Fig.
3). Then I knew that the leopard
male had two doses of zebra, since
zebra is a dominant factor (Norton,
1982b). About half of the offspring
developed the smokey pattern later, so
I knew that the leopard male also had
one dose of smokey. Smokey angelfish
have a dominant gene; the fry, whether
with or without zebra, are striped at
first and then develop the smokey
pattern at a body size of 1 to 1.5 cm
(Norton, 1982a, 1982b). A zebra smokey
angelfish has a pattern almost
identical to smokey (mottled on the
rear half of the body), but with
light-colored spangles in the dorsal
and caudal fins (Norton 1982b).
To produce some fish
genetically like the leopard male, I
mated this male to a double-dose zebra
female. This produced 252 zebra
offspring, about half of which
developed the smokey pattern. There
were no leopards, even thought the
smokey zebra offspring had the same
genetic makeup as that of their
leopard father.
Knowing that the
dotted pattern of the cobra angelfish
develops in zebra lace fry raised in
continuous light, I suspected that the
leopard pattern also might be produced
in smokey zebra fry raised in
continuous light. To test this
possibility, I obtained a spawn from a
silver female and the leopard male;
the fry were raised in continuous
light from one day before they were
free-swimming. None developed the
leopard pattern. About half of them
were smokey.
Figure 3: Zebra angelfish, from
silver female x leopard male.
Figure 4: A zebra angelfish raised in
a continuous
light has black specks, no stripes.
The rest were like
the usual pattern in a zebra raised in
continuous light (Norton, 1982c). They
had tiny black specks, as if sprinkled
with pepper (Fig. 4) but not
the larger dots as in the leopard
pattern. Of course, the flaw in this
test was that these smokeys had only
one dose of zebra instead of two that
were present in their leopard father.
However, instead of repeating the
continuous light test, this time using
a double-dose zebra female in order to
produce some offspring genetically
like the leopard male, I decided to
first try another approach---short
day.
Several years
earlier I had raised some silver
angelfish in a 4-hour day. These did
not develop the usual body stripes of
silver angelfish. Some had a single
stripe on the rear part of the body
(Fig. 5) and some had a large
blotch instead of a complete stripe
(Fig. 6).
Figure 5: Silver angelfish raised in a
4-hour day.
Figure 6: Another silver angelfish
raised in a 4-hour day.
To find out if a
4-hour day would produce the leopard
pattern, I obtained a spawn from a
double-dose zebra female and the
leopard male. About half of the
offspring would be genetically like
their father, and the other half would
be double-dose zebras, like their
mother. The tank containing the fry
was carefully covered with material
impervious to light. The light under
the covering was put on a timer to
turn on the lights for four hours per
day. The fry were fed newly hatched
brine shrimp during the early part of
the light cycle. Being fed only once a
day, these fry grew about half as fast
as angelfish in a 14-hour day and two
brine shrimp feedings per day. At
last! Some developed the leopard
pattern. The rest, about half of them,
were zebras. At about four months of
age, the leopards had a distinctly
spotted pattern on the body (Fig. 7).
They looked like their father did when
I brought him home.
Figure 7: Leopard pattern. One dose of
smokey
and one dose of zebra. 4-hour day.
Figure 8: Zebra (above) and leopard
(below) not
fully developed at 110 days. One dose
of smokey
and two doses of zebra. 8-hour day.
110 days.
Since fry growth
rate is very slow in a 4-hour day, I
wanted to find out if leopards could
be produced in a 8-hour day. I
obtained another spawn from the
double-dose zebra female and the
leopard male, and set the timer for
eight hours of light per day. It was
successful, producing 122 leopards and
128 zebras. At 110 days after the
spawning date, the zebras had stripes
and the leopards had broken stripes
(Fig. 8). At 172 days, the zebras
still were striped and the leopards
had the typical black-spotted pattern
(Fig. 9). These fry grew slowly
because I did not give them a second
brine shrimp feeding each day. The
main thing I was trying to find out is
whether I would get the leopard
pattern with an 8-hour day. To get
faster growth and have the fry
market-ready sooner, more feedings
would be necessary.
Next I wanted to
know if a single-dose zebra
smokey, raised in an 8-hour day, would
develop the leopard pattern like that
of the double-dose zebra
smokey. To test this, I mated a silver
female with the leopard male. The
offspring all had one dose of zebra
(from the leopard parent), and half of
them also had one dose of smokey from
their father. These were raised in an
8-hour day. There were 100 zebras and
99 that appeared intermediate between
leopard and smokey, having a rather
"moth-eaten" appearing smokey pattern
(Fig. 10). Thus, the single
dose zebra plus smokey did not develop
a good leopard pattern.
Figure 9: Leopard. One dose of smokey
and
two doses of zebra. 8-hour day. 172
days.
Figure 10: Pattern intermediate
between smokey
and leopard. One dose of smokey and
one dose of
zebra. 8-hour day.
It is known that a
double dose of smokey produces the
chocolate pattern (Norton, 1982a), in
which most of the body is black. Still
to be tested is whether the leopard
pattern would develop in an 8-hour
chocolate double-dose zebra as it is
in a smokey double-dose zebra. This
information would make it possible to
predict the outcome of using leopard
parents. Crossing leopard with
leopard, and raising the fry in an
8-hour day, would produce one-fourth
zebras (double-dose zebra, without
smokey), one-half leopards
(double-dose zebras plus one dose of
smokey) and one-fourth chocolate
zebras (double-dose zebra plus
double-dose smokey). At least it can
be predicted that no fewer than half
of the offspring would be leopards. Or
fifty-percent leopards can be obtained
from a double-dose zebra female
crossed with a leopard male.
Double-dose zebras can be obtained
from zebra parents. The double-dose
zebras from this cross can be picked
out because they are runts when young,
being about half as large as their
single-dose zebra siblings (Norton,
1982b). These runts grow to good-sized
adults that are prolific breeders.
The age at which
photoperiod-influenced patterns are
"set" and do not change, differs with
the pattern (Norton, 1982c). However,
patterns that are set can remain
unchanged in adult fish. I do not know
how long leopard angelfish must have a
short day length so that the pattern
will not change to smokey after the
fish are switched to a long day. One
commercial fish breeder told me that
he had leopard breeders; if that is
true, then the leopard pattern can be
maintained into adulthood.
Also I do not know
the limit of a short photoperiod to
produce leopard angelfish. The leopard
pattern develops in an 8-hour day, but
not in a 14-hour day, which my fish
ordinarily receive. I do not know what
would be the result of a nine or ten
hour day, for example.
In summary, the
leopard angelfish has two doses of
zebra and one dose of smokey, and it
is raised in a short day. The longest
short day tested is eight hours.
Literature Cited
Norton, J. 1982a. Angelfish genetics.
Part one. Freshwater and Marine
Aquarium 5(No. 4):15-18 et seq.
Norton, J. 1982b. Angelfish genetics.
Part four. Freshwater and Marine
Aquarium 5(No.8):15-17
Norton, J. 1982c. Angelfish genetics.
Part six. Freshwater and Marine
Aquarium 5(No. 10):38-40
Norton, J. 1982d. Angelfish genetics.
Part seven. Freshwater and Marine
Aquarium 5(No. 11)40-41
Half-Black Angelfish
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