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<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). <br /> <br />~ <br />