Marble
Marble may be homozygous, with two alleles for the marble trait (M/M), or it may be heterozygous with one marble allele paired with either a gold marble allele (M/Gm) or with a gold allele (M/g). 

A homozygous marble is mostly black with a small amount of white marbling.  Some marbles will also exhibit orange on the crown. 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.  Both of the ventral fins may be black, both white, or one may be black and the other white.    

A heterozygous marble has a similar appearance to M/M, except that a larger area of the body will be white.  Generally, the amount of white increases some in M/Gm, and increases further in M/g.  However, there is not a distinct demarcation between the amount of white for each genotype. 

As a result of selective breeding, some strains of marble will tend to have more white than others.  It is impossible to accurately identify the genotype without either knowing the genetics of the parents or doing a test cross.  A test cross with a gold angelfish can be used to verify the genotype of a marble.  The phenotypes of the offspring will identify whether one marble allele is paired with another marble allele, a gold marble allele, or a gold allele.   

Silver Marble

A silver marble is a heterozygous marble in which one marble allele is paired with one wild type allele.  The genotype is shown as M/+.  The marble and wild type alleles are co-dominant; the silver marble shows a blending of the two traits.  The angelfish will have a marbled appearance.  However, the coloration will be more muted, with grayish silver instead of white.  This phenotype is sometimes also referred to as a barred marble because the stripes of the wild type can sometimes be seen.       

 

Factors that Affect Expression of the Marble Phenotypes 

 Marble is constant in its expression.  Environmental conditions do not change the phenotype.  Marbles raised under a variety of environmental conditions including different lengths of daily light will always show the marble phenotype.  The black coloration does not fade when the fish is stressed, as it does in the stripes of a wild type.  In a silver marble, when the fish is stressed, the stripes, if present, may fade, much as they do in a silver angelfish.  However, the black marbled areas will not fade. 

 

Changes in the Phenotype as the Angelfish Matures

The marble pattern and coloration is evident in young fry.

Although the black and white coloration is established in very young juvenile 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 any 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.  Some adult marbles may exhibit blue iridescence on other parts of the body, such as a strip of blue iridescence on the caudal peduncle, or small iridescent spangles on random parts of the body.  When an orange crown is present, it may be very light in color or not apparent in a young juvenile, but the color will develop and deepen as the angelfish matures.   

 Additional angelfish phenotypes are formed from the blending of the effects of non-wild alleles at two or more loci. However all of the effects are generally subtle and the marble trait will be the primary expression of each phenotype. 

Interactions of Marble with Non-Wild Alleles at other Loci

The table below shows phenotypes that are formed from interactions between marble and non-wild alleles at other loci. 

Table Notes: [1] Information not available on phenotypic expression of these genotypes. 

Authors of this page have no information on the expression of marble genotypes with zebra.

A marble ghost will be virtually indistinguishable from a marble.  A  marble blushing will exhibit pink blushing in the gill area as a fry and young juvenile.  The blushing may not be visible in the adult as the gill cover become opaque.  However, the fins will be devoid of any horizontal striations and the tail will not show any lacey pattern.

Albino and halfblack are recessive traits that only express when the allele is present in double dose.  Halfblack (h/h) is believed to express when combined with marble genotypes, but no information is available to confirm this.  

Pearlscale is recessive and will only express when present in double dose (p/p). Pearlscale does not modify the color or pattern of a marble, but alters the shape of the scales so they are more reflective of light, resulting in a silvery shine to the non-black areas of the body. 

Veil is a partially dominant allele that results in a veil tail marble in single dose (V/+), and a superveil in double dose (V/V).

 Links to additional information about the marble allele  
Dr. Joanne Norton, FAMA: September 1988, Vol. 11, #9
Dr. Joanne Norton, FAMA: May 1989, Vol.12, #5
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
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