Hydrocynus vittatus

Hydrocynus vittatus, the African tigerfish, tiervis or ngwesh is a freshwater fish distributed throughout much of Africa. This predatory fish is generally a piscivore but it has been observed leaping out of the water and catching barn swallows in flight.

Distribution

Hydrocynus vittatus has a distribution which covers the Niger/Bénoué, Ouémé River, Senegal River, Nile, Omo River, Congo River, Lufira, Lualaba River, Luapula, Zambezi, Limpopo River, Rovuma, Shire River, and Wami River; as well as various lakes: Lake Bangweulu, Mweru, Tanganyika, Upemba, Rukwa, and Malagarazi. It is also found in the Okavango Basin and lower reaches of coastal systems south to the Pongola River and in man-made Lake Kariba, Lake Jozini and Schroda Dam.

Hydrocynus vittatus is common and widespread over most of its range. In the most studied population, that of Lake Kariba on the Middle Zambezi River, the population fluctuated markedly, apparently in direct relation to the abundance of the introduced clupeid Limnothrissa miodon which forms a major part of its diet.

Behaviour

Hydrocynus vittatus mainly live near the bottom of the large freshwater rivers and lakes they inhabit. During the day they tend to be found closer to the surface and then move towards the bottom at night. They thrive in highly oxygenated water in warm climates.

The breeding habits of this species are somewhat elusive but it is thought that spawning may take place over a couple of days during December or January. The timing depends on when the rivers and streams begin to swell due to the start of the rainy season. Females will lay their eggs in submerged vegetation in shallow water close to the shore. Hatchlings will remain in the safety of the vegetation until the water levels become low enough to force them further into the water. Smaller members of this species tends to school together, while larger tigerfish tend to live and hunt alone.

These fish may migrate up to 100 km (62 mi) within the stream or river they inhabit.