'Red Tide Killer'

Some Algae in the sea is very poisonous. Most Algae is harmful if consumed in large quantity by human.
For example the very poisonous one is the one with red pigment.*****

Occasionally, the algae grow very fast or "bloom" and accumulate into dense, visible patches near the surface of the water. "Red Tide" is a common name for such a phenomenon where certain phytoplankton species contain reddish pigments and "bloom" such that the water appears to be colored red.