Roach

• It eats bottom-living invertebrates, zooplankton, plant matter and detritus.
• It lives in nutrient-rich lakes, medium to large rivers and brackish coastal lagoons.
• It has been introduced to Australia and other regions outside its native range.
• It is one of the most abundant and adaptable freshwater fish in Europe, which is why it is used as a reference species in water-quality studies.
• It switches diet according to what is available: zooplankton, bottom-dwelling invertebrates, plants and detritus. That flexibility is the key to its success.
• In lakes where it is abundant it can trigger a cascading effect: by consuming the zooplankton that filters out the algae, it favours green, turbid water.
• It has been introduced into Ireland, Italy, Spain and Australia, among other places, almost always from live bait discarded by anglers.

Skeleton type

Vertebrate - internal bony skeleton (fish)

Habitat & environment

Nutrient-rich lakes, medium to large rivers and brackish coastal lagoons across much of Europe and western Asia

Birth weight

A tiny, transparent larva on hatching

Size at birth

Tiny larva at hatching

Sexual maturity

1-3 years (the male before the female)

Gestation / incubation

1-2 weeks

Litter / clutch size

2,000 to 200,000 eggs per female, depending on body size

Sources consulted: ResearchGate; FishBase; Academia.edu; MDB Fish Fact Sheet; Billouttes.eu; Grokipedia