|
Reprinted with
permission from:
Dr. Joanne Norton
Freshwater And Marine Aquarium magazine
Angelfish Genetics
Photos and Text by Dr. Joanne Norton
FAMA: May 1982, Vol. 5, #5
Naja gold beginning to lose the black pigment on its mouth.
Naja gold pair in two stages of color change to gold.
The male now has only a small black area remaining.
Part Two
About eight mutations in angelfish have
resulted in the many color variations that exist today. Five
of these mutations (dark, stripeless, marble, smokey, and
zebra) were discussed in
Part 1. This article will deal with the three types of
gold angelfish (Naja gold, Hong Kong gold and "New Gold") that
have been widely available in the hobby. Commercial production
of golds today is limited almost entirely to the new gold,
which is gold its entire life (unlike the Naja gold) and has
better color than the Hong Kong gold, in which the juvenile
resembles a faded silver angelfish.
The Naja gold (sometimes called Wingate
gold), which was the first gold angelfish on the market,
appeared in 1970 (Axelrod, 1970). It is the only one of the
tree golds that looks like wild-type (silver) for the first
nine months, more or less, of its life. The first noticeable
change is loss of black pigment on the mouth. Then black
pigment continues to disappear on the lower part of the fish,
while the dorsal areas simultaneously become black. Within a
few days or weeks, the time varying among individuals, these
black areas disappear as the amount of dark area diminishes,
resulting in a gold-colored fish with black pigment remaining
in the eyes of most individuals. Naja golds are the only
angelfish I have seen that have atypical eyes; my impression
is that I can see into the eye's interior.
In the Hong Kong gold (Anon., 1971), the
juvenile is similar to wild-type but its dark markings are
paler. At maturity, this striped pattern disappears and the
fish is gold. Immature Hong Kong golds have an equilibrium
problem. When their light is turned on in the morning, or if
you shine light at them horizontally instead of from above,
they are likely to swim in several head-first somersaults.
This behavior has not been observed in the adults that I have
had.
The new gold angelfish is gold its entire
life. I have examined fry (one day before they became
free-swimming) with 10x magnification, and found that they
have a reduced number of black pigment cells (appearing as
black stipples) compared with wild-type. The new gold never
has the dark stripes that are present in the juvenile Hong
Kong gold. New golds do not have the eye variation that occurs
in Naja golds.
New golds were imported into the U.S. from
Singapore in 1973. Earl Wellwood (1974), a Canadian aquarist,
stated that he had about 5000 new golds before he sold any.
When I talked with Mr. Wellwood in 1976, he told me that he he
thought the new golds on the market originated from his stock.
Unfortunately, his article did not give the date when he first
sold new golds, and therefore he did not make it clear whether
or not he released his new golds early enough for these fish
to have been raised in Singapore and exported in 1973. I have
seen no information on the origin of the Singapore new golds.
Ross Socolof (1975) reported new gold angelfish that appeared
in stocks at his fish farm, and he also said that new golds
turned up in stocks at another Florida fish farm. It is
impossible to know, from the information that I have, whether
the mutation to new gold occurred only once or more than once
within a period of about three years.
Foreground: Naja gold, fully changed to gold.
Foreground: New Gold with one dose of the dominant
gene for veiltail.
It was stated (Anon., 1971) that many
angelfish that were supposed to be Naja golds did not breed
true and that gold parents produced silver young. I do not
know of any documented cases of Naja golds producing young
that never turned gold. However, I know several aquarists,
including myself, who bought young silvers that were sold as
Naja golds and that never turned gold. It seems likely to me
that the price of $5 each for juvenile Naja golds could have
been reason enough for some dishonest dealers to mislabel
young silvers and sell them as Naja golds. Evidence that Naja
golds actually may breed true became available to me when I
visited Adelbert Boxley several years ago. Mr. Boxley, in
Kansas City, had bought some Naja golds from a supplier who
told him that the fish were from gold parents and were
guaranteed to turn gold, which all of them did. He gave me six
juveniles that were offspring from his golds, and all six of
these later turned gold (before they were one year old).
I got all wild-type offspring from a cross
of Naja gold x new gold. Twelve of these were kept for one
year, when they were still wild-type. Thus it appears unlikely
that Naja gold is due to a single dominant gene with complete
penetrance (always being expressed). The possibility that Naja
gold is due to a recessive gene has not been tested, as far as
I know.
Crossing Hong Kong gold with black, I
obtained only black lace offspring. The F2 included 29
wild-type, 49 black lace, 12 black, 4 Hong Kong gold. It is
concluded that Hong Kong gold is due to a recessive gene;
also, that the genes for dark and Hong Kong gold are not
alleles (occurring at the same location on a chromosome),
since mating fish heterozygous for both dark and Hong Kong
gold produced some wild-type offspring.
A blushing (two doses of stripeless) female,
mated to a Hong Kong gold male, produced 100% stripeless
non-gold offspring. The 332 fish in the F2 included 68
wild-type along with some each of blushing, Hong Kong gold
blushing, stripeless, stripeless Hong Kong gold, and Hong Kong
gold. It is concluded that stripeless and Hong Kong gold are
not alleles, since wild-type appeared in the F2 and since Hong
Kong gold blushing (two doses each of Hong Kong gold and
stripeless) would not occur if these two genes were alleles.
Crosses of new gold x new gold produces 100%
new gold offspring. No new golds were produced by matings of
new gold x marble, new gold x black, new gold x smokey, or new
gold x zebra. Each of the backcrosses of new gold x F1 of
these five crosses produced some new gold progeny. Also, a 3:1
ratio (146 wild-type, 50 new gold) was counted for the F2 of
new gold x wild-type. Thus, new gold is due to a recessive
gene.
I would advise anyone who wants to raise
Naja golds to obtain stock from a source that can be trusted
to supply offspring from Naja gold parents. From then on,
these should be mated only Naja gold to Naja gold if the
purpose is to raise this type only. Probably Naja gold stock
is no longer easy to locate since new golds have been
replacing Naja golds commercially.
Hong Kong golds breed true and also should
not be outcrossed with any other color if you want all Hong
Kong gold offspring. The same situation exists for the new
gold, which breeds true.
LITERATURE CITED
Anon. Peter Wong rings the gong in old Hong Kong. Trop. Fish
Hobbyist 19:6-11. January, 1971
Axelrod, Herbert R. Naja's angelfish. Trop. Fish Hobbyist
18:4-13. January 1970
Socolof, Ross, B. Gold, gold now and red, red now. Buntbarsche
Bull. No 47:24. March-April, 1975
Wellwood, Earl. A Canadian creation. Canadian Fish Fanciers 1
(4):16-17. 1974
Angelfish Genetics: Part Three
|
