The Danube lamprey (Eudontomyzon danfordi), which is about 20 cm long, inhabits both mountain streams and larger rivers. Prior to spawning both partners dig circular hollows in the sandy bed and into these the female lays her eggs. The male gyrates around her and fertilizes the spawn. The larvae live between four and five years in the sandy, humus deposits and feed on any organic remnants and diatoms. The adult lamprey attacks other fish, at first cutting their skin with its sharp teeth and then feeding on their blood. In contrast to other related species, it usually lives another two to three years after spawning. It lives in the tributaries of the Danube and the rivers flowing into the Black Sea south of the Danube; however, it is not found in the upper reaches of that river.
The small, non-parasitic freshwater Brook lamprey (Lampetra planeri) is about 15 cm long and spawns from May to June in mountain streams. It can be distinguished from the Danube lamprey by a different teeth arrangement in the funnel-shaped mouth. As in the previous species, the larvae are larger than the adult fish. After reaching adulthood, they develop a sucker disc, their digestive tract is reduced and they mature sexually. Adult brook lampreys die after spawning. The species inhabits the rivers flowing into the North and Baltic Seas and those of north-eastern Italy and Albania.
A similar non-parasitic species, the American brook lamprey (L. lamothenii), lives in the eastern United States.
Maximum size and weight: 20 cm, 100 g.
Characteristic arrangement of horny teeth in funnel-shaped mouth. Lives permanently in freshwaters.
Maximum size and weight: 15 cm, 50 g.
Identifying characteristics: Horny teeth characteristically arranged in the funnel-shaped mouth. Both parts of the dorsal fin connected. Non-migratory