Freeze dried Calanus organisms are produced from our fresh frozen material, thereby providing the aquarist with a product that is as fresh as a product that has just left the water. When feeding freeze dried Calanus it will naturally float which is great for surface feeders ...Freeze dried Calanus organisms are produced from our fresh frozen material, thereby providing the aquarist with a product that is as fresh as a product that has just left the water. When feeding freeze dried Calanus it will naturally float which is great for surface feeders, however if you wish the product to sink, pre-soak your desired amount of food in tank water for a few minutes prior to feeding.