• Dr Norton Article: Pearly, A New Angelfish Mutation

    Dr. Norton's Articles - Part 15
    Reprinted with permission from:
    Dr. Joanne Norton
    Freshwater And Marine Aquarium magazine
    "Pearly" A New Angelfish Mutation
    Photos and Text by Dr. Joanne Norton
    FAMA: December 1990, Vol. 13, #12

    Figure 1: Pearly angelfish
    "Pearly" A New Angelfish Mutation (Sometimes Called Crystal)
    It is exciting to have a new angelfish variety, especially since it has been many years after the last angelfish mutation of merit was found. In recent years new types of angelfish have been produced by making various combinations of already existing mutant genes rather than being due to a new mutation. Pearly is a new mutation that causes a gold angelfish to glitter over most of its body, very unlike any other angelfish.

    I first heard of pearly angelfish when I received a letter from Kamphol Udomritthiruj of Seattle, Washington, in October, 1988. He wrote that he encountered this new angelfish for the first time in the fish markets of Bangkok during the summer of 1987. These fish were being called "pearlscale." He added, "then, they were very sparse and expensive, indicating they were being brought into the market for the very first time. However, the expected introduction of this strain did not manifest itself in America and, peculiarly, upon my return to Bangkok this summer ('88) found them still to be few (too few for such a potentially commercial strain). The appearance is one of tight convolutions of the skin/scales giving the highly reflective appearance of shimmering striations. The pearlscale angelfish that are available are veiltail and standard golds---." He sent me photographs of these angelfish, which look like pearly angelfish that I have.

    Tim Anderson, a tropical fish wholesaler and angelfish breeder in Eagle Grove, Iowa, imported some pearly angelfish from Bangkok early in 1989. These were called "Pearlscale" but, subsequently, the supplier changed the name to "pearly" to avoid confusion with the pearlscale goldfish. Mr. Anderson gave me two of the fish, which were about silver dollar body size (Fig.1). When they grew to breeding size, both were discovered to be females. I crossed one of these females with a gold (non-pearly) male; this produced 153 non-pearly offspring. Later, some of Mr. Anderson's pearlys developed into males, making possible a mating of pearly x pearly. Mr. Anderson told me that these matings produced 100% pearly offspring. He counted several spawns: 276, 197, and 131.

    Figure 2: Close-up of gold angelfish adult, without pearly character.

    Figure 3: Close-up of pearly angelfish adult.

    Because the pearly trait did not appear in the offspring of an outcross (pearly x non-pearly) and because pearly parents produced all pearly offspring, it appeared that pearly is due to a recessive gene. This was confirmed when I counted an F2 spawn: 162 non-pearly, 56 pearly. This is the expected 3:1 ratio if the gene for pearly is recessive.

    No difference was seen in growth rates of pearly and non-pearly angelfish. The pearly character becomes evident in fish that are about nickel to quarter body size. Most dime body size pearlys have little or no pearly development.

    The body of a non-pearly angelfish (Fig. 2), which has a flat surface, is very reflective when front light strikes the fish at a 45 degree angle to the plane of the body, the light aimed from the rear of the fish. The fish is non-reflective when front lighted at a 45 degree angle, aimed from the front of the fish. Thus, a non-pearly angelfish appears either shiny or dull depending on how it is lighted.

    The pearly angelfish, (Fig. 3) has wavy rows of convex scales, creating a bumpy surface. When front-lighted from any angle, the pearly's body has many tiny surfaces that reflect light, resulting in the fascinating sparkle over the entire body.

    The pearly angelfish is unusual enough and beautiful enough to become one of the staples in the angelfish trade and a wonderful addition to the tropical fish hobby.