A cave fisher eats just about any live prey smaller than itself, though anything smaller than a rat isn't much of a meal for it. When a cave fisher captures such a creature, it often leaves the hapless animal entangled, using it as bait to attract larger creatures. Because the adhesive on its filament doesn't last long, the fisher frequently needs to eat one filament and excrete a new one. The filaments are translucent and can be hard to see when they're still and in darkness.