This is my first summer to take care of a pond \:D

I done a search on roundup and found little info.
Sounds like it's hard on frogs. What about fish?

I stocked 50 lbs golden shiners about 3 weeks ago. I been finding a few dead each day. I sprayed some round up sat. morning today 60-100 dead. \:\(

Did I make this worse or is this still natural?