South American catfish in Shillong

The dark brown tropical fish with its beautiful sail-like dorsal fin is a common import for aquariums all over the world, fish experts at the North Eastern Hills University said. This could be a theory to believe as to how the fish got into Umiam lake, they said. "Someone might have found the fish too big for their aquarium and let it directly into the water body where it thrived and found its way to the lake."