These low saline rotifers are an ideal alternative to live Paramecia and have been reared on lnstant Nanno to yield a dense and stable culture. These rotifers are harvested prior to shipping and may be stored in the fridge and then decanted to feed to your fry.; use within 1 week. The rotifers are being cultured at a salinity of 7ppt. Already in use by customers rearing freshwater species including zebrafish and tetras.