Cholla wood is a product from the Cylindropuntia bigelovii Cactus found mainly Mexico and USA. When the cacti die and dry out, the wood remains.However, these cholla is gathered ‘locally’. Because Cholla is hollow it make a great hiding place for baby shrimp and adult shrimp especially while moulting and vulnerable. Cholla will break down over a very long period of time and a bio-film will form on which the shrimp will forage. Tannins will be released into the water which may stain the tank water slightly, but the tannins contain anti-bacterial and antifungal properties which help protect the shrimp. Due to its appealing look it is a great natural alternative for ceramic decoration. DO NOT BOIL THE CHOLLA. Instead, cover it with boiling water and let it soak till it is water logged. Rinse it and add to your tank.