A large number of snakehead fish have appeared in the Deduru Oya reservoir in northwestern Sri Lanka during the past two years. This species is not from Sri Lanka. It usually lives in countries in Southeast Asia. Local officials believed that the fish entered the country through imported ornamental fish. When the fish grew too big for home tanks, some owners may have released them into the reservoir. A researcher named Dr. Kelum Wijenayake said that the snakehead fish has no natural predator in Sri Lanka. Because of this, the species has become strong in the local food chain. Fishermen in the area reported that native fish and shellfish have become fewer. These native species were important for local income. One snakehead fish was reported to weigh about seven kilograms, which is much bigger than most native fish.

The snakehead fish can grow quickly because the reservoir provides warm water and plenty of food. The species can also breathe air from the surface and live in very shallow water. These abilities make it difficult to control. Local fishers suggested promoting angler tourism to help reduce the population. Some producers have begun making salted dried fish from the species, and the product has become popular in nearby markets. Experts said that more harvesting may help protect native fish in the future.