90%-95% is typically considered "high efficiency" for an electric
motor. Of course many manufacturers claim "high efficiency" without
providing data to back up the claim. Also the efficiency of an
electric motor can vary greatly depending on it's load and speed. And
of course the efficiency degrades as the motor or pump gets dirty and
worn.

But back to fish stuff. Do you think that my fish expend any more of
their own energy when in a pond with the pump running than when the
water is quiet? I've noticed that in the winter they congregate in one
end of the pond that has the least circulation.

- Rich