the sandfish exhibits some distinct behaviors. their burrowing behavior varies as they mature, with younger sandfish responding to changes in light and coming out in darkness. older sandfish are more sensitive to changes in temperature and will burrow to escape the cold. sandfish are particular about sediment size and type, settling in fine sand and muddy substrates high in nutrients. like all sea cumbers, "h. scabra" exhibits defensive vomiting, where they expel their internal organs to distract predators while they escape. male and females have distinct mating behaviors; when they spawn males erect their bodies and sway from side to side as they release sperm into the surrounding water. shortly after, females will erect their bodies and send eggs into the water with the sperm in a short, forceful burst.