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.
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.