<br />20 Foreign Nonindigenous Carps and Minnows (Cyprinidae) in the U.S.-A Guide to their Identification
<br />
<br />Similar Species
<br />
<br />The long dorsal fin of the Goldfish, with a
<br />strong, serrated, spinous ray followed by 13 or more
<br />branched rays, distinguishes it from most native North
<br />American cyprinids, which typically have fewer than
<br />II rays and usually lack the spine-like ray. Goldfish
<br />superficially resemble suckers (family Catostomidae),
<br />particularly buffalos (genus Ictiobus) and carpsuck-
<br />ers (genus Carpiodes); however, suckers do not
<br />have spine-like rays in the dorsal and anal fins.
<br />Among foreign non indigenous cyprinids, the
<br />Goldfish most closely resembles the Common Carp and
<br />Crucian Carp. Goldfish lacks barbels, which readily
<br />distinguishes it from the Common Carp (that has two
<br />pairs of barbels). Differences between larval Goldfish
<br />and Common Carp were illustrated by Gerlach (1983).
<br />Goldfish is distinguished from Crucian Carp by its
<br />straight or slightly concave dorsal-fin margin, black-
<br />ish peritoneum, a deeply emarginate caudal fin, and
<br />the absence of a spot at the base of the caudal fin.
<br />Crucian Carp has a slightly convex dorsal-fin margin,
<br />light peritoneum, a slightly emarginate caudal fin,
<br />and a blackish spot at the base of the caudal fin that is
<br />more apparent in juveniles. The posterior margin of the
<br />large, spine-like dorsal ray has 10-11 large denticles in
<br />Goldfish versus 28-29 small denticles in Crucian Carp.
<br />Additionally, the Goldfish is typically slightly less
<br />deep-bodied than Crucian Carp. The pharyngeal teeth
<br />of Goldfish and Crucian Carp are nearly identical.
<br />
<br />Variation
<br />
<br />The Goldfish exhibits a wide range of sizes, shapes,
<br />and colors of the body and fins. Much of the variation
<br />is the result of artificial breeding, and some is due to
<br />natural causes associated with age or growth changes.
<br />For example, as observed in many species, there is an
<br />increase in the number of gill rakers on the first arch
<br />with growth (Dombrovski, 1964, in Szczerbowski,
<br />2001). Artificial selection from a long history of culture
<br />has also intensified variability in body shape and color.
<br />The Goldfish was probably the first cultured fish;
<br />its domestication began thousands of years ago in
<br />China (Balon, 1995). The classic cultured form, known
<br />to aquarists as "Fancy Goldfish" (fig. 13), is reddish
<br />golden with yellow fins; however, artificial selection by
<br />breeders has produced a number of varieties for the pet
<br />trade (for example, Comets, Veiltails, and Shubunkins).
<br />Several varieties have been produced with body colors
<br />of red, white, gold, black, and combinations of these.
<br />Some varieties have been produced that lack a dorsal
<br />
<br />fin, others have greatly elongated fins (especially the
<br />caudal) or multiple fins (especially the caudal and anal),
<br />and some have telescoping eyes (for example, Penzes
<br />and T61g, 1983). Some cultivars may be variegated
<br />and some have no scales. These colorful forms are in
<br />contrast to the wild type, which is generally olivaceous,
<br />varying in color from gray-green, green-brown or gray
<br />(fig. 14). Wild populations of Goldfish often revert to
<br />olive-green coloration, presumably because the brightly
<br />colored ones are eliminated by bird and fish preda-
<br />tors (Moyle, 2002; Wydoski and Whitney, 2003).
<br />In treating Carassius auratus, recent authorities
<br />often recognize two subspecies: Carassius auratus
<br />gibelio (Bloch, 1783), commonly known as Prussian,
<br />Silver Crucian, European Goldfish, or Gibel Carp;
<br />and Carassius auratus auratus, generally referred
<br />to as Goldfish. However, the taxonomy of the genus
<br />Carassius is not fully understood due to a combination
<br />of confounding factors, including wide morphological
<br />variation within purported species, overlap in morphol-
<br />ogy between species (and also between subspecies),
<br />widespread introductions, high frequency ofhybridiza-
<br />tion, and other genetic complexities such as triploidy
<br />(Fuller and others, 1999; Iguchi and others, 2003). In
<br />addition to other nomenclatural disagreements, some
<br />authors recognize gibelio as a separate species rather
<br />than a subspecies under C. auratus. According to
<br />Coad (2005), elongate specimens (morpha humilis)
<br />occur where fish density is high, and deep-bodied
<br />specimens (morpha vovki) occur where fish density is
<br />low; however, the author noted that the names humilis
<br />and vovki have no taxonomic significance. To add to
<br />the confusion, Banarescu (1964) described the same
<br />type variation in body shape for Carassius caras-
<br />sius (see section on variation under account on the
<br />Crucia Carp). Whether Carassius aura/us is a highly
<br />variable species as opposed to a complex of multiple
<br />species may only be resolved by further investigation
<br />combining morphological and molecular analyses.
<br />The Goldfish naturally hybridizes with Common
<br />Carp (see appendix B for meristics) and Crucian
<br />Carp, giving rise to individuals that are intermedi-
<br />ate in morphology between the two parent species
<br />(Smith, 1979; Szczerbowski, 2001). A natural inter-
<br />generic hybrid of Barbus sharpeyi and Carassius
<br />auratus was recently described from a small lake
<br />in Iran (AI-Mukhtar and AI-Hassan, 1999, cited by
<br />Coad, 2005). However, there are no known hybrids
<br />with North American cyprinids. For a listing of other
<br />known hybrids between Goldfish and various Old
<br />World species, refer to Schwartz (1972, 1981).
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