They had round bodies surrounded by several tentacles. Each tentacle had multiple suckers, and two "fingers" on the end. In water and mud, these agile appendages were used to sift through the silt to catch fish and other small prey. On land, they were used to climb trees and forage for fruit. Ludos typically spent the day basking in the treetops, coming down in the early morning to fish or eat the leftovers discarded by larger predators.
Ludos had few natural predators, aside from large carnivorous fish and Ganlihk rippers. Their main defense mechanism against predators was their natural bio-luminescence. When threatened, ludos would try to scare off predators with a burst of bright light, which varied from red to white. They would also try to confuse predators by playing dead and turning off their luminescence, becoming a dull black in color.
Ludos also communicated with one another through a series of trills and piping sounds. These vocalizations were viewed as soothing by many humanoids. A young colonist named Jasten Merew was one of the first to discover the singing creatures, adopting one of them as a "friend." It was said that when he and his parents applauded the music of the ludos, Jasten's friend glowed a particularly bright red.
Some of the colonists on Ganlihk, began to take ludos as pets. Their luminescence and their docile temperaments made them particularly popular. While traveling through Ganlihk's forests, hikers often carried ludos on their backs. The glow of the ludos would ward off predators, and keep parties of hikers in sight of one another.