Moderlieschen (leucaspius Delineatus) And Bitterling (rhodeus Sericeus Anzarus)
Moderlieschen has a slender body, flattened at the sides and with easily detached scales. The lateral line is visible only on the first scales towards the front of the body. Its back is greenish, the belly and sides arc silvery. It may reach a length of between 7 and 9 cm, although it is usually much shorter. It lives in large schools in stagnant or slow- flowing waters which have become overgrown with vegetation. It spawns in April and May, when the female lays her eggs in strips around the stems of water plants and the male fertilizes and subsequently guards them. Its main diet consists of plankton.
Moderlieschen is indigenous to the whole of central and eastern Europe, from the Rhine as far as the watershed of the Volga; it can be found as far north as the rivers of southern Sweden.
The bitterling is a small fish with a high-backed body. On its sides it has a blue-green stripe, which widens out towards the tail. It is quite abundant in the stagnant waters of the lower reaches of rivers, in shallow creeks, in old river backwaters and pools. However, it lives only in waters inhabited by the freshwater mussel, into which the bitterling lays its eggs between April and June. During this period the male becomes reddish-purple at the sides and the female develops a pink ovipositor by means of which she places the eggs within the mantle cavity of the mussel.
It is found all over Europe from north-eastern France as far as the Caspian Sea, but is not present in Denmark, Scandinavia, or the Mediterranean countries. It has been introduced into a number of waters in north-west England. It lives on planktonic crustaceans, insect larvae and worms.
Leucaspius delineatus
Maximum size and weight:
9 cm, 10 g.
Identifying characteristics: Mouth slants upwards, scales large and easily shed. Lateral line developed only on the first 7-13 scales.
Rhodeus sericeus amarus
Maximum size and weight:
8 cm, 15 g.
Identifying characteristics: A blue-green stripe on the sides, widening towards the back. During mating female with long ovipositor, male reddish-purple on sides. Mouth in semi-inferior position; lateral line extends to only 5-6 scales.
