THE Cyprinidae - the carp family-contains the great majority of Europe's freshwater fishes. In the British Isles and western Europe their importance is assessed chiefly in terms of their value as sport or angling interest, but further east, in landlocked countries, they assume a considerable value as food fish. Many of our most familiar freshwater fishes, such as the roach, bream, dace and minnow belong to this family.
The cyprinids have a single dorsal fin which is usually not spiny, although all have one or two long spiny rays as the first supports of the fin, and in certain species these may be very strong and serrated. The pelvic fins are placed near the middle of the body, usually well behind the pectoral fins. All European species have cycloid scales, usually large but occasionally minute; the head is always scaleless. The jaws are toothless, although the lips may be hardened and sharp. Pharyngeal teeth are situated under the gill cover and behind the gill arches. The shape of the teeth, their number and arrangement in one, two or three rows are of importance in exact identification in this group (Fig. 69). They are sited ventrally in the 'throat' of the fish and grind upwards against a horny pad at the base of the skull. The crushed state of the food in the gut of cyprinid fishes is a mute testimony to the efficiency of this mill. The swim bladder in this family is large, divided into two lobes, and communicates with the alimentary canal. The first four vertebrae are modified, and elements form the Weberian apparatus, a chain of small bones connecting the swim bladder with the organ of hearing.
The pharyngeal teeth cannot be examined without killing and dissecting the fish. Their extraction is not difficult but care must be taken in freeing the bone dorsally lest the more exposed teeth be accidentally broken. The method is to cut just inside the gill chamber, immediately in front of the pectoral girdle, from the top of the chamber to the mid-line and thence along the other side. Loose tissue lying between the bones must be cut dorsally, and the pharyngeal bones can be gently pulled forwards and downwards.
Hybrids between two species are common amongst cyprinid fishes. Generally these progeny assume a body form and number of fin-rays intermediate between those of the parent species. Some of the more commonly occurring hybrids are mentioned in the text, but others may occur.
Key to Carp-like fishes of Western Europe. Species absent from the British Isles are marked *
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A. Barbels present at rear of mouth. B |
AA. Barbels absent. F |
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B. Base of dorsal fin short; seven to twelve branched rays. C |
BB. Base of dorsal fin long, seventeen or more branched rays; scales large, but may be absent; anal fin short, the first full length ray serrated. Widely distributed, mainly in ponds, lakes and lowland river reaches.
Carp Cyprinus carpio |
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C. Two barbels, one each side of mouth. E |
CC. Four barbels, a pair in front and a pair at each corner of the mouth; snout elongate; scales medium in size, forty-eight or more in lateral line; dorsal fin high but short, seven to nine branched rays. Widely distributed, in swift-flowing deep rivers. D |
D. Dorsal fin with the hind edge of the spine strongly serrated; fifty-five to sixty-five scales in lateral fine; colour uniform dorsally. Rivers of northern Europe, including England.
Barbel Barbus barbus
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*DD. Dorsal fin with the hind edge of the spine smooth; forty-eight to fifty-five scales in lateral line; dark brown spots on back, sides and dorsal fin. Southern and central Europe.Barbus meridionalis
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E. Barbels long; body elongate, scales large, thirty-eight to forty-four in lateral line; mouth inferior. Widespread in rivers and lakes.
Gudgeon Gobio gobio
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EE. Barbels minute, at corner of mouth, which is terminal; body thick-set, rather rounded; dorsal fin rounded; scales minute. Widespread in ponds, lakes, slow-running river reaches and backwaters.
Tench Tinca tinca |
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F. Dorsal fin base short, fewer than twelve branched rays. H
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FF. Dorsal fin base long; fourteen to twenty-one branched rays, anal base short; five or six branched rays, the last unbranched ray weakly serrate; body deep, normally with large scales.
Carassius G |
G. Lateral line with thirty-two to thirty-five scales; anal fin usually with six branched rays; twenty-six to thirty-one gill rakers on first arch; body deep and rounded in profile. Ponds and stagnant waters.
Crucian Carp Carassius carassius
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GG. Lateral line with twenty-eight to thirty-one scales; anal fin usually with five branched rays; thirty-nine to fifty gill rakers on first arch; body not very deep, back rather compressed. Colour (wild state) silvery green, sometimes bronze.
Goldfish Carassius auratus |
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H. Mouth opening small to moderate, angle of jaw does not extend beyond front of eye; if it does, then eye diameter is greater than snout. I
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*HH. Mouth large, lower jaw prominent; angle of jaw extends beyond front edge of eye; eye much smaller than snout length; body slender and com-pressed; gill slits very wide; restricted to central Europe, in running water but also found in lakes.
Asp Aspius aspius |
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I. Anal fin base long, fourteen or more rays. J
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II. Anal fin base short or moderate, less than fourteen rays. P |
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J. Dorsal fin moderate, approximately in centre of body; pectoral fins not long and curved. K
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*JJ. Dorsal fin very small, set far back, above the anal; pectoral fin long and curved; belly has a strong keel; lateral line sinuous. Baltic and Caspian sea estuaries and lower river reaches of these basins.
Pelecus cultratus |
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K. No keel behind dorsal fin; anal origin usually under the centre of the dorsal fin, occasionally under the last rays; snout rounded and short, equal to the eye diameter or a little longer. L
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*KK. A scaled keel behind the dorsal fin; anal origin well behind the dorsal fin base; snout conical and much longer than eye diameter. Northern Europe in lower reaches of rivers and brackish water.
Vimba vimba |
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L. Anal fin origin beneath the last ray of the dorsal. M
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LL. Anal fin origin beneath the third or fourth dorsal ray; body very deep.
Abramis |
M. Mouth superior or terminal, the opening at pupil level (Fig. 70); snout pointed, lower jaw prominent; scales thin and shiny; small shallowbodied fishes. N
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MM. Mouth ventral; its opening at level of lower edge of eye (Fig. 71); snout rounded; body flattened and deep; scales thick and dull surfaced;
anal fin long, twenty-one to twenty-three branched rays; eight, rarely nine, branched dorsal rays. Ponds and lower reaches of rivers; Europe and eastern England.
Silver Bream Blicca bjoerkna |
N. Mouth superior and not reaching to the front of the eye (see Fig. 70); gill rakers long and numerous, seventeen to twenty-two in number; forty-six to fifty-three scales in lateral line; anal fin has seventeen to twenty branched rays. Rivers and occasionally ponds, England and Wales.
Bleak Alburnus alburnus |
*NN. Mouth terminal extends to front of orbit; gill rakers short and well spaced, fewer than fifteen; forty-seven to fifty-one scales in lateral line; anal fin has fifteen to seventeen branched rays. Swift-running rivers of Europe.
Alburnoides bipunctatus |
O. Mouth inferior; length of base of dorsal fin is half its greatest height; anal fin long, twenty-four to thirty branched rays (usually twenty-six to twenty-nine); fifty-one to sixty scales in lateral line. Lakes, lower reaches of rivers. Widespread.
Bream Abramis brama |
*OO. Mouth oblique and terminal; dorsal fin very high, its base length two and a half to three times in its greatest height; anal fin very long, thirty-five to forty-four branched rays; sixty-six seventy-three scales in the lateral line. Lakes and lower reaches of Baltic rivers.
Abramis ballerus |
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P. Lateral line broken or incomplete, never extending to tail origin. Q |
PP. Lateral line extending to tail fin, S |
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Q . Scales moderately large; lateral line very short. R |
QQ . Scales minute; lateral line reaching anal finlevel or just beyond; dorsal fin has seven branched rays. Small fishes, found in running water and cold-water lakes.
Minnow Phoxinus phoxinus |
*R. Body slim; mouth superior, lower jaw pro-minent; scales fragile and easily detached; lateral line extending only along first ten scales at most; dorsal fin with eight branched rays, anal with ten to thirteen rays. Silvery band along sides. Small fish, living in still or slow-moving European waters.
Leucaspius delineatus |
RR. Body deep; mouth inferior, upper jaw longer; scales firmly attached; lateral line pores on first five or six scales only; dorsal fin has nine to ten branched rays; anal has eight to ten. Iridescent streak on sides from mid-body to tail. Small fish in slow-flowing waters. European,
introduced to U.K.
Bitterling Rhodeus sericeus |
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S. Dorsal fin origin above the base of the pelvic fins; weak scaled keel behind the pelvic fins. T |
SS. Dorsal fin origin clearly behind the base of the pelvic fins (Fig. 72); a scaled keel from the pelvics to the vent; mouth inclined at a steep angle; eight to nine branched dorsal rays. Still waters and slow-flowing rivers.
Rudd Scardinius erythrophthalmus
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*T. Mouth transverse, distinctly ventral, lower lips have sharp, horny edges; snout rather long. U |
TT. Mouth slightly inferior, or terminal; lips soft; snout not elongate. V
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*U. Snout conical, mouth horseshoe-shaped, upper lip thin; fifty-two to fifty-six scales in lateral line. Smaller rivers and streams of southern Europe, especially France.
Chondrostoma toxostoma |
*UU. Snout blunt, mouth transverse or feebly arched; upper lip thick; fifty-seven to sixty-two scales in lateral line. Rivers, particularly the larger rapid ones of central Europe.
Chondrostoma nasus
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V. Seven or eight (exceptionally nine) branched rays in dorsal fin; body slim; pharyngeal teeth in double row.
Leuciscus |
VV. Nine to eleven branched rays in dorsal fin; body deep (humped back) in medium-sized and large specimens; forty-two to forty-five scales; pelvic fin beneath dorsal base (Fig. 73); anal fin has nine to eleven branched rays; pharyngeal teeth in a single row. Widespread in Britain and Europe in still and slow-flowing waters.
Roach Rutilus rutilus
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W. Scales small, forty-eight or more in lateral fine, body slim, head rounded; mouth not
extending to the eye level; anal fin concave or straight edged. X |
WW. Scales large, forty-four to forty-six in lateral line; body thick, head broad; mouth large, gape extending to the eye-level, anal fin rounded in outline (Fig. 74). Rivers and lakes in U.K. and Europe.
Chub Leuciscus (S.) cephalus
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X. Scales moderate in size, forty-eight to fifty--five in lateral fine; eight to nine branched
anal finrays. Y |
XX. Scales small, fifty-five to sixty-one in lateral line; ten branched anal fin rays; mouth terminal, slightly oblique. Running waters and lakes in Europe, introduced to Britain.
Ide (Orfe) Leuciscus (I.) idus |
Y. Sides silvery, not marked with a dark streak from head to tail; body slim, head length greater than body depth at dorsal fin; pectoral fin tip pointed; anal fin concave (Fig. 75). Moderately swift-running, clear waters; widespread.
Dace Leuciscus (L.) leuciscus
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*YY. Dark stripe on sides running from head to tail; body slim, head length at most equal to the body depth at the dorsal; pectoral fin rounded. Running waters over gravel; central and eastern Europe.
Leuciscus (Telestes) soufia and subspecies |
MANY members of the family form hybrids when shoals of spawning fish mingle on the spawning grounds, for several species share a common type of site and time of year. Occasionally, however, a ripe male of one species will apparently deliberately mingle with actively spawning fish of another species and take part in the process. This is particularly true of the rudd, which is a frequent intruder and is a parent species of several common hybrids.
The greatest amount of hybridisation takes place between the more closely related species, and is particularly likely to occur under unnatural conditions, where, for instance, one species has been introduced to a new locality. Hybrids are often recorded as common in certain waters (as the rudd x bream in Lough Erne, Ireland), but are rare in other waters in which both parents occur. Most hybrids are sterile, but fertile males do occur in carp x crucian carp crosses. Females are very rare. In the hybrid between the roach and the bream (Rutilus x Abramis) and the roach x rudd, fertile offspring are common, and certain populations in isolated waters have a complex interbred ancestry. Other hybrids are occasionally fertile.
Many hybrids are difficult to identify with certainty. All have a body form and distinguishing features intermediate between the parent species, but may resemble one parent more closely than the other. The number and shape of the pharyngeal teeth are often the best guide to the identity of the parents. Suspected hybrids of doubtful parentage should be referred to a competent authority for identification. The following notes are a guide only to the more common hybrids; others such as dace x bleak and dace x rudd occur.
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ROACH X RUDD Dorsal fin over rear of pelvic base; the keel between pelvic fins and vent moderate; thirty-nine to forty-two lateral line scales; ten anal rays; pharyngeal teeth in one, more often in two rows (5 + 1 or 5 + 2), slightly serrated. Common. |
ROACH X BLEAK Dorsal fin well behind pelvic base, with eight to eleven soft rays; anal thirteen to fifteen; lateral line forty-five to fifty-two; pharyngeal teeth in a single series (5 -- 5, or 6 -- 5), or in two rows (2 + 5 – 5 + 2, 6 – 5 + 2, 1 + 5 -- 5). Rare.
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ROACH X BREAM Usually deep bodied, but less so than the bream; body more slimy than usual for a roach. Keel behind the pelvic fins is weak and covered with bent scales. Dorsal rays nine to ten; anal fifteen to twenty; forty-two to fifty-four lateral line scales; pharyngeal teeth in a single row of five or six each side, or double with 1 + 6 -- 5, or 6 -- 5 + 1. Common.
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ROACH X SILVER BREAM Keel behind pelvics weak and scaled; dorsal eight to ten rays; anal fourteen to sixteen; lateral line forty-three to forty-six; pharyngeal teeth not serrated, in a single row five each side, or in two rows with 1 or 2 + 5 or 6 teeth each side. Rare.
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RUDD X SILVER BREAM Body deep; keel behind pelvic fins scaled; eyes large (nearly 1/3 of head length); pharyngeal teeth in two series (5 + 2 or 5 + 3) and always with serrated edges; dorsal with eight to nine rays; anal twelve to seventeen rays; lateral line scales forty to forty-seven. Common in Europe.
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RUDD X BREAM Body deep; keel behind pelvic fins moderately sharp and weakly scaled; eye small (1/4 to 1/3 of head length); mouth oblique; dorsal eight to ten rays; anal fifteen to eighteen; lateral line scales forty-six to fifty; pharyngeal teeth in one series (five each side), more often in two series with 1 or 2 + 5 each side; teeth hooked and serrated. Uncommon.
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BLEAK X RUDD Mouth superior; keel behind pelvics sharp; dorsal eight to nine rays; anal fourteen to fifteen; lateral line with forty-four to forty-seven scales; pharyngeal teeth in two rows with 2 or 3 + 4 or 5 teeth, serrated. Very rare.
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BLEAK X CHUB Mouth terminal and oblique; dorsal origin behind the pelvics; a sharp keel behind the pelvic fins; dorsal fin with eight rays; anal with ten to thirteen; lateral line scales forty-five to forty-eight. Not uncommon.
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BREAM X SILVER BREAM Intermediate in most characters, but generally resembling the silver bream in body shape. D. III/8-9; A. III/23-6; lateral line forty-eight to fifty-five; pharyngeal teeth usually in two rows, 5 + 1 or 2 each side. Uncommon.
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CARP X CRUCIAN CARP In body shape similar to the Crucian carp, but in most characters intermediate between the two, including the presence and number of barbels. Usually there are two (one at each corner of the mouth), occasionally one or three, but thinner and shorter than in the carp. D. III-IV/18-19; A. III/5-6; lateral line scales thirty-five to thirty-eight; pharyngeal teeth in two or three rows, usually 3 or 4 + 1 or 2 + 1 . Relatively common.
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A SMALL group, related to the carp-like fishes, they are characterised by having long, rather narrow bodies, toothless jaws, a single dorsal fin sited around the mid-point of the body, and a small, inferior mouth which is surrounded by numerous barbels. Three species are found in Europe, only two in the British Isles, but in Asia there is a vast proliferation of loaches, some of which are imported to Europe as aquarium fish. The European species are nocturnal, and seek shelter by day; two of them are able to utilise atmospheric oxygen for breathing and can live in oxygen-depleted waters such as marshes.