Fig. 1: Cobra angelfish, bought from a wholesaler in 1974.
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| Fig. 1: Cobra angelfish, bought from a wholesaler in 1974. |
In 1974, a tropical fish dealer, Cleo Poe, bought three
"cobra" angelfish from a Minneapolis wholesaler. These had fin
markings like those of a zebra lace (which has one dose of dark
and one or two doses of zebra), and the body was uniformly
covered with dark dots on a gray background (Figure 1).
These cobras, which cost $10.00 each (dealer price), were given
to me with the understanding that I would share the offspring
with Mr. Poe. Unfortunately, they never reproduced, so I did not
learn anything about the inheritance of cobra.
Two years later, Robert Commins wrote an article, "He's
Hoping to Create an Angel," in a Michigan newspaper, The Ann
Arbor News, Wednesday, March 24, 1976. This article was
reprinted in the May-June, 1976, issue of NAC News, the bulletin
of the National Aquarium Club. I could tell from the picture in
that article that the tail pattern of this angelfish, which was
raised and called "cobra" by Ed Sayer, looked like the tail
pattern of the cobras I had two years previously. Although the
body pattern of Mr. Sayer's angelfish was not clear in the
photograph, it appeared to have some dark, vertical partial
stripes, different from the 1974 cobras, which had smaller
markings in the form of fairly uniform dots, with no vertical
bars. According to the Michigan article, Mr. Sayer's cobras had
"black and gray splashes on a silver underlay." The article gave
no information on the genetics or parentage of the fish. The
author stated that Mr. Sayer had many cobras that came from a
cross of two other varieties, of which Mr. Sayer said, "Which
two I'd rather not say."
Over the past eight years I occasionally have made angelfish
crosses in an attempt to produce some cobras like the ones I had
in 1974. It was not until this year that I was successful. After
none of my crosses produced the cobra pattern, I began to
suspect that day length might be a factor. I already knew the
effect of continuous light on the patterns of silver, black lace
and zebra angelfish.
In Part Six I discussed some angelfish pigment patterns that
are altered by continuous light. For example, a silver angelfish
raised by continuous light has no body stripes, and a black lace
is dusky-colored with little or no striping. A zebra angelfish
raised with the lights off at night has three vertical stripes
on the body. In contrast, a zebra raised in continuous light has
only dots and sometimes several very narrow, irregular, vertical
dark markings on the body.
Fig. 2: Zebra lace (one dose of zebra and one dose of dark) raised in continuous light for two months, then at a 14-hour day. Photo taken one year after end of continuous light exposure.
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| Fig. 2: Zebra lace (one dose of zebra and one dose of dark) raised in continuous light for two months, then at a 14-hour day. Photo taken one year after end of continuous light exposure. |
Fig. 3: Zebra lace (one dose of zebra and one dose of dark) raised in continuous light for seven months. This photo taken seven months later.
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| Fig. 3: Zebra lace (one dose of zebra and one dose of dark) raised in continuous light for seven months. This photo taken seven months later. |
I obtained some zebra lace angelfish from a cross of silver
with zebra lace. These, which has one dose of dark and one dose
of zebra, were raised in continuous light for seven months.
Instead of developing the three vertical body stripes
characteristic of zebra lace raised with the lights off at
night, like the fish in Figure 2, these zebra lace had two
partial vertical stripes on a gray background (Figure 3). Some
of the same spawn were raised in continuous light for only two
months and then were switched to a 14-hour day. These looked
like the fish in Figure 3 at two months, but gradually developed
the 3-stripe pattern after they were switched to a 14-hour day.
The photo (Figure 2) was taken one year after the end of the
2-month exposure to continuous light. Unlike the modified black
lace pattern that was "set" by two months of continuous light
(Part Six), the modified zebra lace pattern was not set by only
two months of continuous light.
Fig. 4: Cobra (two doses of zebra and one dose of dark, raised in continuous light), five months old.
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| Fig. 4: Cobra (two doses of zebra and one dose of dark, raised in continuous light), five months old. |
I still did not have the dotted pattern, with no vertical
bars, of the 1974 cobras. I then decided to raise in continuous
light some zebra lace with two doses of zebra. I had a pair of
zebra lace that were double-dose zebra (each produced 100% zebra
offspring, some with and some without dark, when tested by
crossing with wild-type). These zebra lace, each of which had
two doses of zebra and one dose of dark, were mated, which
produced zebra, black and zebra lace offspring, all having two
doses of zebra; they were raised in continuous light. At last!
There were three different patterns in the offspring: light ones
(double-dose zebra, no dark), black (double -dose zebra,
double-dose dark), and dark ones (two doses of zebra and one
dose of dark). The dark one (Figure 4) looked exactly like the
1974 cobras, having dark dots on a gray background, and no
stripes or partial stripes.
Many organisms that are affected by day length will react the
same to various lengths of long day. for example, and 18-hour
day might produce the same results as a 20-hour day. I have not
raised angelfish in an extremely long day, with the lights off
only a few hours at night, to see if this has the same effect as
continuous light on their patterns.
Fig. 5: Each of these fish has two doses of zebra.
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| Fig. 5: Each of these fish has two doses of zebra. |
Fig. 6: Black zebra (two doses of dark and two doses of zebra).
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| Fig. 6: Black zebra (two doses of dark and two doses of zebra). |
Cobra angelfish are not true breeding since they are
heterozygous for dark (one dose of dark). It may be possible to
raise spawns of 100% cobra angelfish. To do this, you would need
to cross a female double-dose zebra (Figure 5) with a black
zebra male (Figure 6, two doses of zebra and two doses of dark).
I suggest using a black zebra male rather than female since
black males without zebra can be effective breeders for numerous
spawns, while black females may spawn only a few times and then
quit reproducing. The required breeders can be obtained from any
zebra lace parents, which produce zebra, zebra lace and black
offspring, and also silver and black lace if both parents have
only one dose of zebra. The slow-growing zebras would be the
ones to select, since they are the ones with two doses of zebra
(see Part Four). The black zebras also are slow-growing, like
blacks without zebra.
If the black double-dose zebra proves to be a poor breeder,
which would not surprise me, then the next best way to get
cobras is from zebra lace parents. You can get 50% cobras from
zebra lace parents that are homozygous for zebra (two doses of
zebra and one dose of dark). There will be some of this type of
zebra lace in spawns in which both parents are zebra lace.
Again, select the slow-growing zebra lace, as these are the ones
likely to have two doses of zebra. A zebra lace can be tested by
mating it with silver. If it is a double-dose zebra, then all of
the offspring of this cross will have the zebra pattern (three
vertical stripes), with or without dark, so there will be 50%
zebra and 50% zebra lace.
The cobra angelfish is no longer a mystery; it can be raised
by anyone who knows what parents to use and that the spawns
should be raised in continuous light. I have never seen cobra
angelfish in shops or in shows, so I have the impression that
they are rare in the hobby and trade. Perhaps, with knowledge
now available on how to produce them, more of this attractive
angelfish will be seen in the future. It is important, however,
for anyone who buys cobra angelfish to realize that these fish
will produce no cobra offspring if the spawns are raised with
the lights off for a long period (how long is not yet known) at
night.
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