The decanaut has adapted well to living in the open ocean. With their roots now free from the nutrient-poor soil, they have become more active. Like the colony crystals, the roots of the decanaut will project a caustic sphere of influence that will digest any cell unfortunate enough to stray into it. In order to aid in the capture of cells, the epidermis of the roots is lined with long tinsel flagella that ensnare cells killed by the enzymes. Because the crystalline portion of the octocrystal now lies above water, the shell has now developed spiracles that allow the shell access to carbon dioxide while simultaneously preventing desiccation. Like their ancestor, the decanaut hibernates. However, this hibernation is slightly shorter, as the decanaut will remain active in the first part of the winter, relying on filter-feeding. Once the number of microbes present becomes too low for the decanaut to continue feeding, the decanaut begins to hibernate.
Because the decanaut are so far apart in the open ocean, their method of reproduction has changed dramatically. Instead of producing simple gametes that will die shortly after being released, the gametes now contain all of the organelles required for survival outside of the parent crystal. This allows for the gametes to exist for an indefinite amount of time, increasing the chances of them coming into contact with another gamete. These gametes are produced at the base of the crystal, and are washed into the ocean when the decanaut's reproductive pores come into contact with the water.