nyrfrx, Welcome to Pond Boss.Theo gives you some great winter aeration information.In a small pond also be sure when attempting to open up a small area in the ice with bottom diffused aeration that you understand that the bubbles will "trail off" in an uncontrolled fashion until the hole is realized.This can create thin ice in unpredicted areas.In a pond that has an age of 15 years and if no supplemental aeration has been done in the past and ice fishing is wanted consider cutting a hole in the ice and stuffing a bale of straw in it. It will refreeze solid around the bale and the 15 year old pond can breathe all winter. Be sure to double twine the bale as the strings may come apart from the water weight. Also run two doll rods through it at the ice line so the rods are on top of the ice and supporting it. This works well in small ponds especially in Ohio. Older ponds can have a higher demand for oxygen than newer (5 year or less) ponds.They can also have some gasses that would be beneficial to let vent off from under the ice.All of this may of been covered in the links Theo provided, (thanks Theo)