The foreign species, not native to Pakistan, is believed to have accidentally entered natural water bodies and has now spread across Sindh and parts of lower Punjab.

Handlers initially described the fish as an unidentified alien species.

Experts warn that the fish has spread so widely that eradication or effective control is no longer possible.

The Amazon sailfin catfish, native to Latin America, is characterised by a body covered with bony plates and a thick, armoured structure.

While popular globally as an aquarium fish, it is also recognised as a highly successful invasive species.

This species adds to a growing list of at least 26 non-native fish introduced into Pakistan, either deliberately or accidentally, which have become invasive.

These species are disrupting natural ecosystems and harming aquatic biodiversity.

Pakistan’s first alien fish species, brown trout and rainbow trout, were introduced in 1928 in areas now part of Khyber Pakhtunkhwa.

Over the decades, other non-native species, such as Mozambique tilapia, common carp, goldfish, grass carp, silver carp, bighead carp, Nile tilapia, and blue tilapia, were introduced to boost fish production or control aquatic weeds.

Many of these species have since established themselves in natural water bodies, affecting native plants and animals.

Experts note that while the goal of introducing these fish was to enhance aquaculture output, the long-term environmental impacts were largely overlooked.

World Wide Fund for Nature (WWF) Pakistan has stated that there is a broad consensus that alien fish species have negatively affected the country’s aquatic biodiversity and ecosystems.