Oxygen in a pond
Maintaining the right oxygen levels in a pond can be crucial if you want to avoid future problems, or keep whatever lives there in a healthy condition. Also, to be scientifically correct, we are talking about dissolved oxygen (utilized by vegetation and wildlife).
Note: This article is mainly addressed to farmers and those with larger constructions but can very well be of use if you have a garden or smaller fish pond.
Dissolved Oxygen
Dissolved oxygen in a pond is the primary and most important life support for both animals and vegetation.
It occurs naturally in the atmosphere and in water - to a certain degree. Too little (below 3 ppm) can stress or kill the inhabitants of a pond, whether it be fish or plant.
Therefore, testing and maintaining oxygen levels in a pond is of the outmost essence.
Low Oxygen Levels in a Pond
High Oxygen Levels in a Pond
Can you have too much oxygen in a pond?
The answer is usually no. Fish, crustaceans or plants will not be harmed by too much oxygen as any surplus will get released into the air.
However, if you use an oversized aerator to oxygenate your pond the flow could be so high that it creates larger bubbles - which will not produce as much dissolved oxygen as one with the right dimensions (for your pond).