There are several types of zander, the best known being the Common Zander (Sander lucioperca), which occurs widely across Europe. It is laterally compressed and has a distinctive double dorsal fin containing hard and quite sharp rays. It is very similar to the Perch but can be distinguished by an additional spine on its operculum and distinctive coloration.
This fish is often a greenish or brown color with dark vertical markings on the flanks, which can be used to help identify it. There is also a characteristic cream or white belly. The zander (Sander lucioperca) and its close relative, the European pikeperch (Sander lucioperca) are among the largest predators in European freshwaters. They are both anadromous filter feeders, which means that they move into rivers in spring to spawn and then spend the rest of the year in the sea. They are capable of growing up to at least 1.5 m long with a weight over 20 kg, although most fish caught are around 60 cm long and weigh between 3–5 kg. In Norwegian rivers, they can weigh up to 7 kg.
Zander is very similar in appearance to the perch and hybridizes readily with it when kept together in aquaria; both species grow to a similar size of around 25 cm and tend to feed on small fish and invertebrates. However, zander possesses the characteristic double-spined dorsal fin of the pike-perch family. This fin, which is higher in front than behind, has 13 to 15 spiny rays and nine soft rays at its rear end. The spine on the operculum (gill cover), which is also found in perch, helps distinguish zander from perch during their initial phase of life, as they are very similar species.
Zander has a distinctive dark-colored body with irregularly shaped vertical stripes on their sides which provide good camouflage when resting amongst aquatic plants. These markings become paler during the spawning season and fade away during the winter months.
Both species can reach up to 50 cm or more, weighing about 5 kg or more. More typical adult size is around 40 cm and 2–3 kg. Although they are predators, the prey of these fish includes small crustaceans, amphibians, and waterfowl (especially ducklings).
Zander is sexually mature at ages 3–4 for females and 5–6 years for males. Spawning takes place between February and May when water temperatures are above 10 °C. They move into shallow backwaters to spawn over gravel or pebble beds. Females can lay up to 30,000 eggs which are guarded by the male.
After hatching, the male continues to guard the young for several weeks. Young Zander usually moves into deeper water after a few weeks and starts feeding on their own. Zander is euryhaline so can live in both freshwater and seawater. Some have been recorded as living for up to 14 years.