Anchovies

What they lack in size, anchovies make up for in numbers. The largest shoals consist of countless millions of individuals, all creating their route through the untamed ocean 
in search of food.

Like all shoaling fish, anchovies convey with one another and so are equipped to swim in close formation. Their silvery sides help them do this by providing a visual aid. However, anchovies are unusual in that they can also use pulses of sound to keep in touch with each other when swimming at high speed.