|Species Status||Not threatened|
Hydruka were created by the Makuta using various Viruses and liquid protodermis.
Hydruka were herd Rahi of the inhabitants of Mahri Nui. They were used by the Matoran in that area to harvest Airweed, which they used to create air bubbles needed to live safely underwater. Hydruka were the favorite prey for Ehlek's eels. They still remained in the sea after Mahri Nui was destroyed and the Matoran left.