Per the SEClear Algaeide label you should only treat ½ of the pond at a time, as there will be oxygen loss when killing off the algae and weeds. To prevent harming the fish you should begin your treatment along the shore and move outward in bands so that the fish can move into untreated water. Wait 14 days and then treat the other half of the pond.
The product label of SeClear Algaecide states "This pesticide is toxic to fish and aquatic invertebrates. Waters treated with this product may be hazardous to aquatic organisms. Treatment of aquatic weeds and algae can result in oxygen loss from the decomposition of dead algae and weeds. This oxygen loss can cause fish and invertebrate suffocation. To minimize this hazard, do not treat more than ½ the water to avoid depleation of oxygen.
For applications in water that will be used for drinking water, those waters must receive addtional and separate potable water treatment.
Please view more information under the Environmental Hazards Section of the product label.
