Sulphur mollies move in waves to evade predators
While fish are generally no match for predatory birds that hunt them from above, the sulphur molly, a freshwater fish species which can grow up to 4.5 inches, appear to have developed an effective defence mechanism.
When the school spots a potential predator (not necessarily birds, but any other species that may prove a threat, including humans), the school start swimming in waves that were conspicuous, repetitive and rhythmic.
And it is not just a few hundred sulphur mollies involved in this display—we're talking about a much larger number.