• Dr Norton Article: Introduction, Genetics Of The Mutant Genes, and Practical Applications

    Dr. Norton's Articles - Part 1
    Reprinted with permission from:

    Dr. Joanne Norton
    Freshwater And Marine Aquarium magazine
    Angelfish Genetics
    Photos and Text by Dr. Joanne Norton
    FAMA: April 1982, Vol. 5, #4

    A male wild-type (silver) angelfish.

    Part One

    Before 1950, only wild-type (silver) angelfish existed in the tropical fish trade. Since then, mutations have resulted in a number of color patterns: black lace, black, ghost, blushing, smokey, marble, chocolate, zebra, and several different golds. A search of the scientific literature yielded no reference on the inheritance of color patterns in angelfish. The first recorded mutation resulted in the black lace angelfish, which appeared in about 1953 in Europe. Black lace is similar to wild-type but has intensified black pigmentation. Innes (1955) discussed this "partially black" fish. Since all it took to get black angelfish was to obtain a spawn from black lace parents, it is not surprising that a number of aquarists soon and almost simultaneously had black angelfish, which were reported by Innes (July, 1955), Ludwig (June, 1955) and Wolfsheimer (July, 1955).

    Ross Socolof told me that he found an angelfish sport without stripes in 1961, named it "white ghost," and had been selling it for about two years before the "Conles blushing" angelfish (named by Lester Boisvert) appeared (Vorderwinkler, 1965). Blushing angelfish have no body stripes or spots and the juveniles have red gill areas. Mr. Vorderwinkler stated that blushing individuals appeared in spawns from the "white ghost" strain, but did not discuss the genetics of either ghost or blushing.

    About twelve years ago, two more angelfish mutations, marble (Ash, 1969) and smokey (Ash, 1971) were discovered by Charles Ash. The marble angelfish has a black-marbled body and its fins are streaked with black and white. Marble fry, on the first day that they swim, are darker than wild-type fry. The smokey angelfish has a splotchy dark pattern on the rear half of the body, black-tipped dorsal and anal fins, black in much of the caudal fin, and black on the mouth.

    I do not know of any published account on the origin of the zebra angelfish, which entered the trade in the 1970's. In this pattern, there are three prominent vertical stripes on the body. Single-dose zebras also have more (up to 12) light-colored horizontal bars in the dorsal fin than in wild-type, which has about 7 or 8. Zebra angelfish are slightly darker-colored than wild-type at about 3 weeks after they become free swimming.

    As far as I know, there have been three kinds of gold angelfish in the hobby: first, Naja gold: second, Hong Kong gold: and, third "new gold." These will be discussed in Part 2.

    Genetics Of The Mutant Genes

    It is known (Norton, 1971) that dark is an incomplete dominant that produces black lace when present in single dose. A double dose of dark results in a black angelfish. By using a flashlight to strongly light the body of a black angelfish, you can detect faint vertical body stripes. Although the black lace angelfish is as vigorous as wild-type, the true black (double dose of dark) is less vigorous and is slow growing.

    Marble is an incomplete dominant (Norton, 1971). In single dose, this gene produces a black and white marble pattern. Most individuals having two doses of marble have a more intensely-pigmented and more extensive black pattern, with smaller and fewer white areas than in a single-dose marble. A mating of intensely-pigmented marbles produced 100% offspring like the parents. These fry were slow-growing, taking about twice as long to reach marketable size as it would take for single-dose marbles. A dark-patterned marble angelfish that I suspected had two doses of marble was mated to wild-type; this produced 412 light-patterned marble offspring, the expected result if the marble parent had two doses of marble. While double-dose marble angelfish lack vigor and are slow-growing, single-dose marbles appear at least as vigorous as wild-type. Matings of light-patterned marbles with wild-type gave the expected 1:1 ratio if the marble parent had one dose of marble. A wild-type female X light-patterned marble male produced 231 light patterned marble and 207 wild-type. A wild-type male gave 46 light-patterned marble and 41 wild-type.

    Stripeless is an incomplete dominant that, in single dose, produces "ghost," a fish without body stripes; a double dose of stripeless results in blushing (Norton, 1971), a fish without body stripes or spots, but with a black vertical bar below the eye and another black vertical bar at the base of the caudal fin. A juvenile blushing angelfish has a greatly decreased number of iridophores, resulting in translucent rather than reflective gill plates; therefore the red gill color is visible. In a mature blushing angelfish, the red gill area disappears because iridophores develop in the opercular tissue, as well as in patches on the body and fins. When I removed scales from a reflective area of a dead mature blushing angelfish, I found that the reflective tissue is underneath the scales. The mature blushing male has a more pronounced hump on his head than usually develops in other types of male angelfish. Also, mature blushing angelfish, unlike other colors of angelfish, do no have red color in the iris of the eye. Expression of stripeless in single dose is variable, the body having no black markings, or with one or more black blotches on each side. A female with no stripes, but with one large oval black spot about 2 cm in length on the rear part of the body on each side (see photo), was tested by mating her to a blushing male. This produced some each of blushing and stripeless offspring, the expected result if the one-spot female had one dose of stripeless. Another female with no stripes but with two large oval black spots on each side of the body was mated to a blushing male. Again, stripeless and blushing offspring were produced; thus the two-spot female also had one dose of stripeless.

    One dose of stripeless does not appear to decrease vigor. However, the blushing angelfish is less vigorous and slower-growing than wild-type; thus a double dose of stripeless decreases vigor. I have had spawns of blushing in which the incidence of defective swim bladders ("belly sliders") in the fry was high. Young blushing angelfish are unusually susceptible to fin infections, and they must have frequent large water changes to prevent infection of the tips of their dorsal and anal fins. I have encountered unusually small fry in some spawns of blushing angelfish. These were not able to eat 36 hour brine shrimp nauplii (San Francisco), but could eat, for about the first two days, nauplii that had a 24 hour hatch time and therefore were smaller than 36 hour nauplii.

    No zebra offspring have appeared when neither parent had the zebra pattern. A wild-type female mated to a zebra male produced both wild-type and zebra offspring. Two of the F1 zebras were mated, producing 70 zebras and 26 wild-type, the expected 3:1 ratio if zebra is due to a dominant gene. Single-dose zebras appear equal in vigor and growth rate to wild-type.

    Crosses of wild-type (with no smokey background) X smokey gave the expected 1:1 ratio if the smokey parent in each case had one dose of a dominant gene. The result of these crosses were:

    1. wild-type female X smokey male: 53 smokey, 54 wild-type
    2. smokey female X wild-type male: 222 smokey, 231 wild-type
    3. wild-type female X smokey male: 241 smokey, 262 wild-type
    4. wild-type female X smokey male: 426 smokey, 418 wild type
    5. wild-type female X smokey male: 98 smokey, 105 wild type

    Smokey parents produced three kinds of offspring: wild-type, smokey, and chocolate. Suspecting that chocolate had a double dose of smokey, I crossed a wild-type female with a chocolate male; this produced 100% smokey offspring. Thus the gene for smokey is an incomplete dominant, producing chocolate in double dose. In chocolate, the dark pattern is more extensive than in smokey. Chocolate was named by Adrien (1973) but its genetics was not discussed. I have noticed no diminished vigor or growth rate in either smokey or chocolate angelfish, compared with wild-type.

    For approximately two weeks after becoming free swimming, smokey and chocolate fry appear identical to wild-type. Then, within two or three days, the anal fin darkens in smokey and chocolate fry, compared with wild-type. Some of these lose stripes and develop the smokey (or chocolate) body pattern in about three more days. Time of development of this pattern varies among individuals, but all have a posteriorly-mottled body at four to six weeks after hatching (at 80degress F), usually when the body diameter is between 1 and 1.5 cm.

    Practical Applications
    Whatever type of angelfish you want to raise, you will benefit by obtaining spawns consisting of only one type, not two or more types. Sorting hundreds or thousands of angelfish is a time-comsuming nuisance for the aquarist. In large-scale commercial angelfish production involving as many as tens of thousands of angelfish per week, the time and labor used for sorting can be very expensive. Sorting often is made even more difficult and time-consuming by the fact that many angelfish patterns (including wild-type, black lace, smokey, chocolate and zebra) fade when the fish are disturbed. In such cases, it is necessary to sort a few until the patterns begin to fade on those fish left in the tank, than wait perhaps several hours to sort more after the patterns reappear.

    Most aquarist and even many commercial angelfish producers often raise angelfish from breeders that produce mixed spawns. For example, black lace parents are used to produce black lace angelfish, even though this is not the cross that produces 100% black lace offspring. There are other cases in which the best cross to get a certain type requires using parents that are not like the offspring you want. Following are the crosses that will produce the greatest percent of the desired type.

    Black Lace
    Mating black lace x black lace will produce 25% wild-type, 50% black lace, and 25% black. You may harvest a lower percent of blacks than this since the fry mortality rate of black angelfish is high. To obtain 100% black lace, use a wild-type (silver) female and a true black male. The reason for not crossing a black female with a wild-type male is that it is common for black females to produce only a few spawns (Norton, 1971). Many of the black-colored angelfish in the trade today are not true black (having two doses of the gene for dark). You can obtain true blacks by saving the blacks from black lace parents. The blacks should be raised separately from the rest of the spawn as soon as you can segregate them because they are slow growing and well not grow as will if kept with the faster-growing black lace and wild-type siblings.

    A male black lace (one dose of dark).

    True black (two doses of dark) angelfish are not vigorous and, even though they breed true, they have been replaced largely with other genetic types of blacks which are more vigorous. These other kinds of black angelfish will be discussed in a future article of this series.

    A male black (two doses of dark).

    Since a blushing angelfish has two doses of the gene for stripeless, the only cross to produce 100% blushing offspring is blushing x blushing.

    A word of caution to those aquarist who raise angelfish with other fishes, such as swordtails or mollies: This works for most angelfish, but blushing is an exception. Mollies may pick at the bodies of blushing angelfish, sometimes killing all of the blushing angelfish in a tank within a day or two.

    A juvenile blushing (two doses of stripeless)

    A male blushing, adult (two doses of stripeless)

    I do not know of anyone producing ghost (one dose of stripeless) angelfish commercially. However, 100% ghost angelfish will be produced by mating blushing with with wild type.

    Ghost (one dose of stripeless)

    Ghost (one dose of stripeless) with one spot.

    Ghost (one dose of stripeless) with two spots.

    Ghost (one dose of stripeless) with black bar.

    Double-dose marble angelfish are true-breeding, but since they are frail and slow-growing, they are not economical to raise. The hardy and fast-growing single-dose marble is preferable, but is not true breeding. From single-dose marble parents (which have less black and more white than in double-dose marble) you will get 25% dark (double-dose) marble, 50% light (single-dose) marble, 25% wild-type. This is unsatisfactory not only because of the sorting required but because the two kinds of marble angelfish grow at different rates and will not reach marketable size at the same time. The best mating to produce marble offspring having no other kind of mutant gene is double-dose marble x wild-type. (Another commercially valuable marble, having more than one kind of mutant gene, will be discussed in a future article.) Double-dose marble angelfish are not common in the trade, but you can obtain some from a spawn of single-dose marble parents. You will know that you used single-dose marble parents if you get wild-type, light-colored marbles, and dark-colored marbles (having little white), and no other type. While the fry are small, 1/2" or less total length, segregate the darkest ones, which also will be the smallest. Most or all of these will be double-dose marbles, which should be raised by themselves so that their growth will not be inhibited by their larger siblings.

    Male marble (one dose of marble)

    Smokey and Chocolate
    Smokey angelfish should not be produced by using smokey breeders because this will give 25% wild-type, 50% smokey, and 25% chocolate. You will get 100% smokey offspring by mating wild-type with chocolate. Since chocolate angelfish are seldom offered for sale, they usually must be obtained from smokey parents. From then on, you can maintain a chocolate strain, since chocolate angelfish breed true.

    Male smokey veil (one dose of smokey)

    Male chocolate (two doses of smokey)

    Zebra angelfish are not raised commercially, although zebra lace is common. Zebra lace, which has one dose of zebra and dark, will be discussed in a future article.

    Foreground: Zebra female (one dose of zebra)


    Adrien, Daniel O. Hybridization in angels. Buntbarsche Bull. No. 38, pp32-34, 1973
    Ash, Charles A. The new marble angel. The Aquarium 2 (No. 3):4. 1969
    Ash, Charles A. The smokey gray veil angel. The Aquarium 6 (No.6):8-9. 1971
    Innes, Wm. T. Introducing perfected black angels. The Aquarium 24:205-207. 1955
    Ludwig, Fred. Tropical Fish Hobbyist, June, 1955
    Norton, Joanne. Angelfish-breeding and genetics. The Aquarium 6 (No. 10):34-41. 1971
    Vorderwinkler, William. The Conles blushing angelfish. Tropical Fish Hobbyist 13:5-9. 1965
    Wolfsheimer, Gene. Black angels. Aquarium Journal 26:177-178. 1955