Sunset (Gold Blushing)
Multiple Locus Phenotype

Non-wild alleles that interact to form this phenotype:

• Gold (g)

• Stripeless (S)

A gold blushing angelfish is a gold angelfish with the addition of two stripeless alleles.  It has the phenotype: 

g/g – S/S

Two stripeless alleles makes it a blushing angelfish.  While young, the angelfish will have a clear pink circular area over the gills.  The pink is from the color of freshly oxygenated blood in the gills, showing through the translucent gill covers.  The pink area may become partially or completely masked in the adult fish. 

Other effects are associated with the double dose of the stripeless allele.  The body color will be white instead of colored like a gold angelfish.  As an adult this phenotype will develop iridescent silvery-gold patches on its body, which result are caused by guanine deposits.  The adult fish is also characterized by a lack of striations in the dorsal fin.

Another common name for the gold blushing phenotype is “sunset.”  Some people only call this phenotype a sunset when it exhibits orange coloration in the crown, and others will use the term for any gold blushing angelfish.  Several years ago, an orange crown was considered a good achievement in  breeding sunsets.  Today some of the top breeders have developed strains that exhibit orange over a large percentage of the body. 

Development of the orange color is variable in its expression, and sometimes does not express at all.  It is believed to be influenced by environmental factors, as with the orange coloration in a gold marble blushing (koi) angelfish.  No definitive studies have been performed to determine which environmental factors play the most significant role.