Lertas are tiny, aquatic animals native to Gamila's Paddleton Sea. They feed by removing small scraps of food from larger creatures, using their long mouths to pull things out of crevices and scales. They also emit a low hum, which, when there are many Lertas around, can create a sound like that of a gigantic predator. This scares away other creatures. In return, the animal the Lertas latch on to gives them food. The hum is also known to play a role in the mating process.