After losing nine of my largest fish (about a foot long ) to a heron I
took a motion detector like you use for your outside lights and
connected it to a fire alarm strobe light and put the motion detector on
the "test" mode so it would work during the day time. It has been three
months and no more fish have been taken. You must use a small 24 volt
transformer with this set up and a rectifier that costs under two
dollars.
=A0=A0=A0=A0The flash of that strobe is more than they can stand but it
is not somthing that will hurt or kill them.
Steve