Table 1. Angelfish Gene Mutations Categorized According to Characteristic Group

Order

Characteristic Group

Gene Mutation (symbol)

1^st

color

marble (M), black (B), gold (g), and gold marble (gM)

2^nd

stripes

stripeless (S), zebra (Z)

3^rd

fintype

veiltail (V)

4^th

half-black

half-black (h)

5^th

smokey

smokey (S_m)

6^th

pearlscale

pearlscale (p)

7^th

albino

albino (a)

Table 3. Phenotypes Resulting from 3 or more Mutation groups in Angelfish*

Genotype

Phenotype

+/B ZZ */* +/* +/Sm¹

cobra pattern²

¹An asterisk (*) is like a wildcard in that it signifies that any gene for the group could be present and still result in the designated phenotype.

²We have produced these beautiful fish by crossing a chocolate leopard (+/+ Z/Z +/+ +/+ Sm/Sm) with a double black double zebra (B/B Z/Z).

Note: The cobra has been previously defined as +/+ Z/Z +/+ +/+ Sm/+ grown with a long photoperiod. We prefer to define a variety by appearance and discuss separately the genetic and environmental variations that can be used to produce the variety. In this case we found another way to produce a fish that looks just like the cobra that was grown with a long photoperiod.

Table 4. Phenotypes of Angelfish not Explained by Mendelian Genetics

Phenotype

Discussion

Orange Pigmentation

Orange pigmentation appears in many varieties of angelfish including silver angels (+/+). However, it shows up best in white areas of Koi angels (gM/gM S/S or gM/g S/S) and White Blushing Angels (g/g S/S) . Orange pigmentation is naturally concentrated in the crown area (dorsal area of body between the mouth and the base of the dorsal fin) but can also occur on any body part. This characteristic does not appear to behave according to Mendelian rules.

The propensity of the orange characteristic to be enhanced is similar to the enhancement propensity of black marbling in marble, koi, and gold marble angelfish. In these 3 varieties, black marbling can be selected to produce fish that are almost all black. Likewise, in Koi, orange can be selected to produce fish that are all orange.

It seems that the expression of orange may be genetically related to marbling based on our experience of enhancing orange by out breeding to marble angels and backcrossing. Also, Koi that are over 85% orange with very little marbling can produce fish with extensive marbling. However, the orange pigmentation of koi seems to be linked somehow to the gold marble gene because out breeding to pure white blushers with no orange (g/g S/S), followed by backcrossing the offspring, does not produce orange pigmentation. Therefore, the mechanism by which out breeding to marble angelfish enhances coverage with orange cannot be explained

Orange pigmentation can be selected in white blushers too, although the results of this have not produced fish as orange as the best orange koi. One form of orange pigmentation in white blushing angels is the orange crowned white blusher which has a distinct orange crown. This may be what some angelfish breeders call a sunset blusher. We have also produced fish in which the orange crown was transferred to the ventral area as orange streaks extending into the ventral fin.  Recently a fish was produced in our hatchery with an orange patch which we believe may have been the result of “crossing over” from the chromosome carrying the gM gene in orange koi angels to the g gene.

Stripe pattern in gold marble angelfish

The presence of one or more apparent black stripes or partial stripes in gold marble angels suggests that an interaction between M of gM and the wildtype stripe (+) may exist. However, breeding fish with this characteristic does not appear to increase the strength of the phenotype or the frequency of its occurrence in the offspring. In fact, our experience with breeding gold marble angelfish with "marble stripes" resulted in broods without any occurrence of  the characteristic.

Swallowtail

This characteristic is a partially split anal fin which shows up sporadically in many angelfish hatcheries including ours. We have produced viable offspring when breeding 2 fish with the swallowtail characteristic, but none of the offspring were swallowtails. I have heard that some normal finned parents throw a few Swallowtails in every brood. If this is true, it suggests that the swallowtail characteristic has a genetic basis and is not just a developmental abnormality. If this is true, it suggests that this characteristic might be transmittable but not apparently according to Mendel's Law.

Perhaps if a discreet Mendelian gene for swallowtail exists, it is a gene for potential expression dependent on certain environmental conditions?

Fantail

Blue coloration

Many breeders are trying to select for blue pigmentation which is observed as iridescence in the fins and scales of almost all angelfish varieties. Some wildcaught angelfish have spectacular blue irridescent mottling reminiscent of discus. The varieties most commonly chosen for blue selection appear to be blushing, smokey blushing and chocolate blushing. Blue coloration is also prominent in varieties carrying zebra genes and in silvers. We do not know the biological basis for the blue coloration, nor if it can be enhanced by supplementation with a nutrient like carotenoids in orange angelfish.

The blue comes in many shades: indigo, greenish blue, sky blue..... An all blue angelfish of discus quality has yet to be developed.