Order:	Cypriniformes
Family:	Cyprinidae
Genus and species:	Rutilus erythrophthalmus

William Yarrell (1836) in "A History of British Fishes":

THE RED-EYE. RUDD.

ROUD. Norfolk. - FINSCALE. SHALLOW.

Leuciscus	erythropthalmus,		Cuvier, Règne An. t. ii. p. 276.
"	"	Red-eye,	Flem. Brit. An. p. 188, sp. 66.
Cyprinus	"		Linnæus. Bloch, pt. i. pl. 1.
"	"	Rudd and Shallow,	Penn. Brit. Zool. vol. iii. p. 479, pl. 83.
"	"	Red-eye,	Don. Brit. Fish. pl. 40.
"	"	"	Rudd, Roud, and Finscale,	Willughby, 249 & 252, Q. 3, f. 1.

The species belonging to the second division of the genus Leuciscus of Klein have the dorsal fin placed so far behind the line of the ventrals as to bring it over the space between the ventral and anal fins.

To this second division belong four British species, the largest of which, the Rudd, or Red-eye, is a very common fish in Europe, as well as in various localities in this country. It is found in the Thames, and other waters near London ; and I have seen some dozens together for sale in Hungerford fish-market. It is found in Oxfordshire and Warwickshire. It is the Shallow of the Cam and the Lode, two rivers in Cambridgeshire. It is abundant in the broads of Norfolk, where it is called Roud, a name that occurs in Willughby : it is also common in Lincolnshire and Yorkshire. It is recorded as occurring in Scotland; and I have seen specimens from Lough Neagh in Ireland, where it is universally called a Roach.
The name of Rudd attached to this species is derived from the prevailing golden coppery tint which ornaments the whole surface : the term Red-eye refers to the colour of the irides ; it is also a translation of the trivial name applied to this fish, which is further distinguished in several countries of Europe by names that have reference to the red colour of its scales or its eyes.
The Rudd, in addition to its vivid colours, is also tenacious of life, and is on that account preferred by trollers as a bait for Pike. It breeds freely without requiring any care to be bestowed upon it, and is therefore useful as food for large Perch, Trout, or Pike. It is said to be a much better fish to eat than the Roach, but does not attain more than two pounds' weight. The food of the Rudd is worms, molluscous animals, and insects, with some vegetable matter: it spawns in April, or early in May, on or about aquatic plants, and the scales at this period are rough to the hand.
The length of the head compared to the length of the head and body is as two to seven : if measured to the forked centre of the caudal rays, as one to four : the depth of the body is to the same length as one to three: the head small ; the nose rather blunt ; the diameter of the eye one-fourth of the length of the whole head ; nostrils in a circular depression half-way between the point of the nose and the anterior edge of the orbit ; the nape and back rise suddenly, the whole dorsal line very convex ; the fleshy portion of the tail narrow ; abdominal line also very convex, the depth of the body decreasing suddenly from the commencement of the anal fin. The scales large ; the number in the series forming the lateral line about forty, in an oblique line ascending to the dorsal fin seven, and descending to the line of the ventral fin four; the scales having numerous concentric striæ, and two or three radiating lines. The dorsal fin is placed very far back ; the first ray arises half-way between the point of the nose and the end of the short central caudal rays ; the base of the whole dorsal fin over the space between the ventral and anal fins; the base of the dorsal fin equal to the length of the sixth ray. From the point of the nose to the commencement of the pectoral fin, from thence to the origin of the ventral fin, and thence to the anal aperture, are three very nearly equal distances; the anal fin commences in a vertical line but little behind the origin of the last ray of the dorsal fin, the base of the fin equal to the length of the second or longest ray ; the caudal rays rather long, the longest as long again as the central short rays. The fin-rays in number are -

D. 10 : P. 15 : V. 9 : A. 13 : C. 19.

The Irish specimens of Rudd from Lough Neagh had one ray more in the dorsal and anal fins.
The irides are orange red ; the cheeks and gill-covers golden yellow ; upper part of the back brown, tinged with green and blue ; the sides more pale ; the belly light golden yellow ; the whole surface of the body tinged with a brilliant reddish golden hue, varying when viewed in different positions in reference to the light, which it is difficult to name correctly ; the fins more or less bright cinnabar red, particularly in those specimens which I have seen from the Thames, Cambridgeshire, and Lough Neagh ; dorsal and caudal fins not so bright in colour as the fins of the under surface, but more inclining to reddish brown.
Walton says, "There is a kind of bastard small Roach, that breeds in ponds, with a very forked tail, and of a very small size ; which some say is bred by the Bream and right Roach ; and some ponds are stored with these beyond belief; and knowing men that know their difference call them Ruds: they differ from the true Roach as much as a Herring from a Pilchard. And these bastard breed of Roach are now scattered in many rivers; but I think not in the Thames. "Under the account of the Bream, he adds - "Some say that Bream and Roaches will mix their eggs and melt together ; and so there is in many places a bastard breed of Breams, that never come to be either large or good, but very numerous."
It is probable that the fishes here alluded to were the true Rudd, and the second species of Bream, which have been already described; and an opinion apparently prevailed, notwithstanding the numbers in which they existed, that they were hybrids. The instances in which animals in a truly unlimited natural state make selections beyond their own species are probably very rare. Hybrids and permanent varieties are the consequence of restriction and domestication, and I confess my doubts of the existence of hybrid fishes.

Frank Buckland (1880) in "Natural History of British Fishes":

RUDD.

(Scardinius erytropthalmus)

Local names: Finscale, Red-eye, Roud, Rudd, Shallow. German: Das Rothauge. French: La Rotengle.

THE Rudd (Leuciscus, or Cyprinus erythropthalmus), or Roud, as it is known in the Norfolk vernacular, is very plentiful in the Norfolk broads, and especially those north-west of Yarmouth. Their colour varies much. In some shallow broads they are of a bright golden hue ; in others, where the water is deep, their scales are like those of a roach or dace. A small red worm, gentles, and a paste made with honey and flour, will sometimes be taken freely when all others fail.
In Land and Water, vol. xviii., August 8, 1874, my friend, Dr. Norman, gives the following valuable experiences relative to Rudd fishing in Norfolk: “The best bait is a nice red worm, but the finest fish are taken with a salmon gut foot line and three hooks, a large float, and at least forty yards of strong light line. I have had a brace weighing nearly five pounds several times on my paternoster, and many years ago caught twenty-nine in a few hours, scaling over four stone. The ground should be very carefully baited for two days at least, and a long willow wand stuck in the mud in the middle of it. Anchor the boat very quietly twenty-five or thirty yards off, throw your float near the willow, and you will have such sport as few will imagine. It is really a case of no sooner in than under; and, as an old piscatorial friend said, after an hour’s hard work, ‘Even in my wildest dreams, doctor, I never had such splendid fishing.’ I once took three at a single cast of the line that weighed over five pounds, and a very pretty commotion they made in the water. Another evening, after a very early tea, we landed no less than 194. Sunrise and sunset suit these fish best, but I have had capital sport on a hot autumn day, although that is rather rare.”
For the most part the rudd frequents the same districts as the roach. One diagnostic point between these two fish is as follows : In the dorsal fin of the roach it will be found that the front ray stands almost even with the front ray of the central fin, but in the rudd the dorsal fin stands evenly between the anal and ventral fins. The eye in the rudd is of a much brighter red than the roach.

Alwyne Wheeler (1969) in "The Fishes of the British Isles and North West Europe":

Rudd

Scardinius erythrophthalmus (Linnaeus, 1758)

NAMES Fr. Rotengle; Du. Ruisvoorn; Ge. Rotfeder; Da. Rudskalle; Sw. Sarv; Nor. Sörv.

IDENTIFICATION A deep-bodied fish, with a moderately large mouth, terminal but strongly oblique, and without barbels. The dorsal and anal fin margins are concave. The dorsal fin origin is well behind the pelvic fin base, and has usually eight, sometimes nine, branched rays. The scales are large, firmly attached, the free edge equal in depth to the eye diameter. A sharp keel, covered with scales, runs along the belly between the pelvic and anal fins. Pharyngeal teeth are in two rows, 5 + 3, each side (Fig. 69). It grows to an average length of 8-10 in (20-25 cm), less frequently to 12 in (30 cm) and only exceptionally to 16 in (41 cm) and a weight of 2.2 lb (1 kg). The British record rod-caught fish weighed 4 lb 8 oz (2.06 kg).
The colour is variable, the head, back and sides usually being a brownish green and the sides a brassy yellow, fading to white on the belly. The dorsal and tail fins are brown with a red tinge, but the pectoral, pelvic and anal fins are blood red, grey at the base. The iris is golden, with a red spot above.
D. III/8-9; A. III 10-11; lateral line scales 40-5; transverse scales 7-8/3-5; vertebrae 36-9.

BIOLOGY A widespread but irregularly distributed species in still and slowly flowing waters, it is found both in lakes and rivers. While most common in the waters of the lowland plains (it is found in brackish water) it also occurs at altitudes of 6000 ft (1829 m). The rudd is a fish of the middle and surface water, feeding less near the bottom than the roach.
The rudd attains sexual maturity in the third or fourth year of life, at a length of 4½-5½ in (11-14 cm). It spawns from April to June, generally beginning when the water temperature reaches 18°C (64°F). The season is often extended, possibly as a result of falls in temperature which result in intermittent spawning. The males assume a brilliant breeding dress with heightened coloration and fine white tubercles on the head and body scales. The eggs are shed on submerged vegetation along the shore-line and on the edges of reed banks. The eggs are 1-1.4 mm in diameter and hatch in from eight to fifteen days according to the temperature. The alevins are 4.5 mm long at hatching and hang for the first few days on the vegetation. Thereafter their growth varies greatly with local conditions and habitat. Exceptionally good growth has been recorded as 4 in (9.8 cm) in one year, 6 in (15.4 cm) in two years and 8 in (20.7 cm) in three years. Poor growth in a population may, however, mean that three-year fishes average 3 in (7.5 cm) and at six years they are still only 4¾ in (12 cm). The normal growth rate in most larger British waters is somewhere between these extremes.
The food of the rudd is similar to that of the roach, but also reflects its more pelagic mode of life; in particular they eat adult surface or aerial insects. The insect portion of their diet contains adult waterboatmen (Corixa spp.), water-beetles and Diptera, also larval Trichoptera and chironomids (blood-worms). The main crustaceans are mid-water copepods and ostracods, but they also eat the fresh water shrimp Gammarus. They eat a small amount of plant material, including diatoms, filamentous algae and higher plants. Young rudd eat diatoms, algae and copepods mainly; the larger ones are wholly carnivorous. Occasionally large rudd eat fish, usually young roach or bleak.
Rudd have some economic importance in eastern Europe and are fished for commercially with seine-nets and traps. Their flesh is not, however, considered to be particularly palatable. Their value in western Europe is chiefly as a sporting fish and they have considerable appeal to the angler, due to their abundance in lowland waters, their good size and their readiness to take a bait. Small specimens make good bait and also serve as a food fish for other more desirable predators.

DISTRIBUTION

Also a subspecies S. e. scardafa (Bonaparte, 1832) in northern Italy and the Adriatic basin.