Abstract: There is disclosed a method of improving water quality, the method comprising adding a pool of isolated Daphnia to a body of water such that the pool of isolated Daphnia is exposed to one or more contaminants which may be in the water. The pool of isolated Daphnia comprise Daphnia which have been resurrected from dormant Daphnia. The pool of isolated Daphnia are allowed to filter from the body of water at least a portion of said one or more contaminants to reduce the level of the one or more contaminants in the body of water. After a period of time, at least a portion of the Daphnia containing said one or more contaminants are removed from the body of water, thereby improving the water quality of the body of water.