I started 2 days ago to aerate my pond (its about 3/4of an acre in size) and this morning I found over two dozen dead fish on the edge of the pond. Anything from a 6 inch cat to a 5 pound cat and brim in all sizes. It looks like they swam right up the edge. Can I put to much air in to the pond? I am using a small air-compressor to pump in the air until I get my new pump in so that's why I am wondering if it is to much. Also what is a good way to test the water for a good balance.
Thanks

What are you using for diffusers, where are they at in the pond (depth) and did you follow the usual start-up procedure?

What kind of compressor are you using?

The compressor is a pancake type with no oiler. Explain the start up procedure? It is a stone diffuser I put in a 5 gallon bucket with gravel in the bottom.

You need to start aeration gradually, increasing aeration time slowly to avoid a fish kill which it sounds like you may have precipitated.

Yes I guess the pump put out a lot more air then I thought. So I will leave it off until I get the smaller pump and then start again with 15 minutes at a time.

Aeration is one of the best ways to improve the quality of your pond. Inproperly designed systems and incorrectly starting up the system is one of the easiest ways to kill a bunch of fish. The archives is full of good advice on this subject. Other than site selection and pond construction this is the application that most needs professional advice.

start up cliff notes:

15 min run time the first day

30 min run time the 2nd day

keep doubling the time every day until you have it running 24/7.