Cholla Wood Skeletons are the remains after a cholla plant dies. It is a soft wood which provides a food source for biofilm that shrimp will feed on, similar to what leaves do. The cholla's may holes provides hiding places for shrimp after they molt or when they are feeling vulnerable. Plus, it provides a natural and attractive way to maintain slightly acidic pH levels in freshwater aquariums.
Cholla wood is light and buoyant and will decompose after a year or so.