Part of my original world, Phephelune http://phephelune.tumblr.com/

Merfolk are fish-like amphibious humanoids that come in a variety of shapes and color, depending on their environment. They live in the oceans as well as lakes, rivers, and swamps. Their communities unify in sounds, filtering their energies through each other with the melodies they sing together. Some of these melodies may sound horrific to outsiders, but it is all very therapeutic to the merfolk of that community.