Silurus Glanis

Datasheet

General Description

The Wels Catfish, scientifically known as Silurus Glanis, is a large freshwater species belonging to the family Siluridae. It is among the largest freshwater fish globally, capable of exceeding 260 cm in length and weighing over 165 kg. With a lifespan of 80 years or more, this species is a nocturnal carnivore that primarily preys on fishes and crustaceans in its natural habitat.

Aquarium Setup

For tank setup, the Wels Catfish requires a minimum tank size of 20,000 liters. The aquarium should maintain water conditions with a hardness of 3-25°dH, a pH range of 6.0-8.0, and a temperature between 3.9-20°C. Decor choices range from sandy substrates to large driftwood pieces, smooth rocks, and hiding spots like piping. Water quality upkeep and moderate lighting are essential, along with a robust filtration system and strict maintenance routines.

Behaviour

Wels Catfish is non-gregarious and tends to be territorial with conspecifics. However, a study conducted in the Rhône River observed occasional formations of temporary aggregations comprising more than ten individuals throughout the year. These groupings were not linked to migratory or schooling behavior, reproduction, or foraging and lacked a distinct explanation. Larger species are recommended as tank mates to avoid predation.

Feeding and Diet

As primarily nocturnal and opportunistic feeders, Wels Catfish prey on various aquatic creatures, including fishes, crustaceans, amphibians, insects, and occasionally young waterfowl or small mammals in the wild. In captivity, they readily adapt to consuming dead alternatives like prawns, mussels, squid, whitebait, and larger fish strips.

Reproduction & Dimorphism

In the wild, Wels Catfish engage in spawning migrations from February to April, depositing adhesive-coated eggs in vegetated areas near lakes, floodplains, and river deltas. Males guard the eggs during incubation, which lasts 2-10 days. Sexual dimorphism is visible in males possessing serrations on the pectoral fin spines, absent in females. Sexual maturity is typically reached at 3-4 years of age.

Habitat and Distribution

Found in lowland river channels and lakes, Wels Catfish seldom venture into smaller tributaries except during early life stages. They prefer deep, slow-flowing river stretches. Native to regions draining into various seas, including North, Baltic, Black, Caspian, and Aral seas, their distribution spans Eastern Europe to parts of Western and Southern Europe following historical introductions. They are established in countries like France, Spain, Italy, and Kazakhstan, with thriving populations noted in rivers like Po in Italy and Ebro in Spain.