Phibians are a fictional race in the Dune universe first mentioned in Chapterhouse: Dune. They are primitive humanoid fish creatures brought as captives to the "million planets" by the Honored Matres. They appear in Hunters of Dune.
Phibians are genetically wrought humanoids, a mingling of human and fish with a limited capacity for intelligence and vocabulary. Created out in The Scattering, they have bullet-shaped heads and lean and streamlined bodies taller than humans and slick green skin that 'shines with oily iridescence'. On Buzzell the Honored Matres used the Phibians as overseers for the Bene Gesserit slaves as well as to retrieve soostones from the sea; as the Phibians are capable of breathing underwater as well as on land, they can dive deeper and farther from shore than any human can. The Phibians like spice, and for years traded soostones for spice with smugglers. After the Bene Gesserit conquered Buzzell Murbella made a deal with the Phibians to stop this trade.[1]