ReefPods are a tropicall species of benthic copepod. These copepods eat detritus, left over fishfood, fish waste, plant debris and microalgae. They will rapidly populate a marine environment-your tank. They are small which makes them suited for many juvenile and adult organisms and are generally not harmed by pumps or powerheads. Reef Safe, they will not harm your setup or corals and in fact make an excellent supplementary food source for them. They are a distinct population which has been cultured for many years to handle the conditions of a closed aquarium setting. There are approximately 100-200 per package along with macroalgae, some microalgae (phytoplankton) food and naturaltreated seawater (treated with ozone, carbon, uv).We recommend several options for using the ReefPods. They can be added directly to the tank. They can be added directly to a refugium. They can be placed in a container and fed out as desired. If there is a wrasse or mandarin living in your tank already do not be surprised if the copepod population does not take off. They love Reefpods! A ReefPod population that is flourishing will be evident by the moving specs on the sides of the tank either during the "day" or "night" cycle.