Rudd

Name in dialect: coe rosse.

Rudd have a high, broad body shape and large scales (40 – 45 can be counted along the lateral line), greenish-brown back, silvery reflections on the flanks and a pale belly. The eyes are red to orange in colour. The pectoral, ventral and anal fins are a reddish brown, the dorsal and caudal fins brown to grey. In young rudd, the tail fin is red (hence their nickname “code rosse”) and on the caudal peduncle there is a large black spot. Adults can grow to lengths of around 35 cm and weights of 1 kg, but shoals are often made up of specimens weighing two to three hundred grams.
Rudd are very adaptable, and live in almost all still and slow flowing, warm waters, with muddy beds, rich in plant life. They are one of the least sensitive species to strong variations in dissolved oxygen content; they also benefit from the eutrophication of waters, going to occupy niches that are no longer suitable for more discerning fish that are more exciting to fish, such as tench and perch.
Rudd move about in shoals, near reed beds along banks and shores. They are omnivorous and spawn from April to July, depending on water temperature. Each female deposits tens of thousands of small, reddish brown eggs (diameter 1 mm), which stick to the underwater vegetation. The fry hatch after 8-10 days and remain attached to the vegetation until the yolk sac has been reabsorbed. They have been known to cross breed with roach.
Rudd are not a good food fish. Eutrophication of Lake Caldonazzo at the end of the 1970s led to an over-proliferation of rudd, to the detriment of other, more valuable species. Over ten tonnes of rudd had to be removed from the lake using nets.