I live in southeastern Indiana in a rural area.  I am looking at installing a Geothermal Heat and cooling system.  I have a pond that is over 1 acre and at the deepest is 16ft and during drought it never goes below 9ft.  The pond is 50' away from the house 3000sqft.

My questions are:

* Will the temp. change from the coils kill off the fish or cause any problems enviormentally for them? (blue gill, bass, fatheads and chanel catfish)
* Will the winter temp of the pond be good for heating.
* Even though we have 13 acres of land it is almost all rock and it is not possible dig.  What is the efficancy difference between the pond loop and well?

Any help would be appreciated.

You will be fine with a pond that large and deep.  Also the fish species you mention thrive in a very wide range of temperatures.

You will not have a problem making the water too cold as your pond is over 8ft deep.  Plant deciduous trees around it to shade it in summer to help mitigate dumping heat into it.