Plecoceramics Cichlids rocks aquarium decoration is made of clay firing at high temperature. This makes our ornament absolutely safe for people, aquarium fish and pets. The Boulder Cichlid Stone fish house can be used for providing hiding places for fish and reducing agression among them. Fish tank decoration looks very natural inside tank. Just flush the rock in running water before using. Can be used for dwarf cichlids, crayfish, plecos, betta fish and others small aquarium fish.