Topmouth gudgeon (stone moroco, false razbora) – Pseudorasbora parva

The topmouth gudgeon, also known as stone moroco and false razbora, has mainly been introduced in the same manner as aquaculture species such as carp and Asian carp, but partly also as bait fish and for aquariums and fish ponds. The topmouth gudgeon spawns early, at the age of one year. In the species’ native range, spawning begins when the water reaches a temperature of 15–19 degrees Celsius in May-August, but in Europe the species spawns earlier in April-June. Females carry 400-5,000 yellow ellipsoidal eggs (2–2.5 mm). The spawned eggs stick to stones on shorelines, vegetation and other substrates. Before spawning, the female cleans the substrate and the male guards the eggs until they hatch. Embryonic development takes 4 to 8 days at a water temperature of 20–28 degrees.

The topmouth gudgeon feeds on plankton crustaceans, fish fry and young fish. Its maximum size is 11 cm and it has a life span of 3 to 5 years. The species prefers shallow lakes, channels, ditches, slow-flowing rivers and vegetated areas. It spreads easily, even into open water areas.