Last week I wrote to Scott's who makes a wide variety of chemicals and
fertilizers. Here is what they replied to my question about
Miracle-Gro.

Hello,

It is safe to use Miracle Gro All Purpose Plant Food near a body of
water, but not in the water.

The nutrients in Miracle-Gro are, in general, are toxic to fish. They
upset the ionic balance of the metabolic system.

I would suggest you contact your local county extension agent for
recommendations regarding aquatic life. The number should be listed in
your telephone directory under "County Offices".

Again, thank you for your interest in Miracle Gro. Please feel free to
contact our company anytime wemay be of assistance.

Kathy Obenour
Consumer Response Representative
The Scotts Company and Subsidiaries
14111 Scottslawn Road
Marysville, OH 43041

Hope this helps some,

Paul
www.pondkoi.com