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Dark Locus: Gold Marble Phenotypes

The allele for gold marble is on the dark locus and is designated with the symbol Gm. 

The non-wild alleles at this locus that appear in gold marble phenotypes are:
Gold Marble (Gm), Gold (g)

Gold Marble

Gold marble (Gm) exhibits co-dominance (blending of traits) with the wild type allele (+).  It is recessive to the black (D) and the marble (M) alleles and is dominant over the gold (g) allele. 

Two distinct phenotypes of gold marble occur: gold marble and silver gold marble.   The table below summarizes how the allele for marble interacts with other alleles at this locus to form the gold marble phenotypes. 


Phenotype Common Name Gold marble

Silver Gold Marble

(Barred Gold Marble)

Genotype: Gm/Gm or Gm/g Gm/+
Pattern of inheritance: Gold marble is dominant to Gold. Co-dominant with wild type (blending of traits)

Gold Marble

Gold marble may be homozygous with two alleles for the gold marble trait (Gm/Gm) or it may be heterozygous with one gold marble allele paired with one gold allele (Gm/g). 

 Gold Marble

A gold marble is predominantly pale gold colored with random black markings. The tail, dorsal and anal fins will typically exhibit some combination of black and white bands or stripes running the length of the tail or fin.  Occasionally an entire fin or tail may be completely white or completely black.  The ventral fins may both be black, both white, or one may be black and the other white.  The crown is typically darker than the body, with a dark yellow to orange coloration.  

A heterozygous gold marble (Gm/g) will generally exhibit less area with black markings than a homozygous gold marble (Gm/Gm).  Sometimes the black markings may only consist of one or two small black spots.  However, the amount of black can very from one fish to another, and from one strain to another, making it generally difficult to determine the genotype accurately in most gold marbles.  

 Silver Gold Marble
Silver Gold Marble

A silver gold marble is a heterozygous marble in which one marble allele is paired with one wild type allele.  The genotype is shown as Gm/+.  The gold marble and wild type alleles are co-dominant, and the silver gold marble shows a blending of the two traits.  The coloration will be more muted, grayish silver instead of gold, with black random black patches.  The stripes of the wild silver type will typically be present, thus it is also often called a barred gold marble.       

Factors that Affect Expression of the Gold Marble Phenotype:
Gold marble is constant in its expression.  Environmental conditions do not change the phenotype.  Gold marbles raised under a variety of environmental conditions including different lengths of daily light will always show the gold marble phenotype.  The black coloration of the marbling does not fade when the fish is stressed.  In the silver gold marble, however, the stripes will fade when the fish is stressed or frightened, as do the stripes in a wild type angelfish, whereas the black color of the marbled markings will not fade. 

Changes in the Phenotype as the Angelfish Matures
The marble pattern and coloration is evident in young fry. Although the black markings are established in very young juvenile gold marbles, some subtler but distinct changes occur as a juvenile matures into an adult.  The most obvious change is the development of horizontal striations in the white stripes in the dorsal fin; these striations have blue iridescent bands.  The iridescence shows most intensely when the angelfish is either exhibiting a territorial behavior or is preparing to spawn. 

Gene Interactions

A number of additional phenotypes can be formed when gold marble phenotypes are combined with non-wild alleles of other genes. All of these phenotypes still are predominantly gold marble in appearance. 

Probably the most popular phenotype is the gold marble blushing, which results from the addition of two stripeless alleles (S/S) to gold marble. When the crown is yellow to orange, gold marble blushing is commonly called koi.

The table below summarizes phenotypes that can be formed from combining gold marble phenotypes with non-wild alleles at other loci.

Phenotypes resulting from Gold Marble + Alleles at other Loci

Alleles Gm/Gm, Gm/g Gm/+
Z/+, Z/Z [1] Zebra Gold Marble


Gold Marble Ghost Silver Gold Marble Ghost
S/S Gold Marble Blushing (Koi) Silver Gold Marble Blushing (Blue Koi)
Blue Koi
S/Z Gold Marble Clown Gold Marble
Sm/+ Smokey Gold Marble Smokey Gold Marble
Sm/Sm Chocolate Gold Marble Chocolate Gold Marble
h/h Gold Marble Halfblack Silver Gold Marble Halfblack
a/a Albino Gold Marble Albino Silver GoldMarble


Gold Marble Pearlscale Silver Gold Marble Pearlscale
V/+ Gold Marble Veil Tail Silver Gold Marble Veil Tail
V/V Gold Marble Super Veil Tail Silver Gold Marble Super Veil Tail

Table note: [1] Information was not found to confirm the interaction between gold marble and zebra.

Links to additional information about the gold marble allele
Dr. Joanne Norton, FAMA: September 1988, Vol. 11, #9
Dr. Joanne Norton, FAMA: May 1990, Vol. 13, #5
Dr. Joanne Norton, FAMA: December 1993, Vol. 16, #12

Approved by The Angelfish Society Standards Committee on February 11, 2007.

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Web Team Updated   08/26/2009