Water hyacinth (Eichhornia crassipes) is called the 'Terror of Bengal'. It is an exotic species which is not native to Bengal. But once it got introduced into the water bodies of Bengal, it grew very fast and competed with the native species eliminating many of them. It depleted the dissolved oxygen in the water bodies leading to large scale loss of aquatic life, particularly fishes. This is why water hyacinth is referred to as the 'terror of Bengal'