API Accu-Clear Water Clarifier quickly clears cloudy aquarium water by eliminating haze and restoring crystal-clear clarity. It works by clumping tiny floating particles together into larger particles that can be easily removed by the aquarium filter. Accu-Clear is safe for use with all freshwater fish and plants. It can also help clear cloudiness caused by bacterial blooms, but it does not treat the underlying cause, so the cloudiness may return unless the main cause of the bacterial bloom is addressed.