Water & Oxygen koi sturgeon pond

The amount of oxygen dissolving in water is dependant on the temperature of the water. This would mean that as temperature increases the maximum amount of oxygen that will dissolve decreases. As a fish keeper it is vital to understand the physical relationship between water and gas, and to be aware of the conditions that cause oxygen deficiancies which will cause stress to the fish in your pond. Koi and sturgeon need a minimum of 6mg per litre of oxygen in the water and this is achieved by the continuation of water flow via a pump and filter 24 hours a day 365 days of the year. No ponds should have their pumps turned off at night, it would amaze you how many people turn off the power to their ponds at night to save money only to wake to find alot of fatalities in their pond due to oxygen starvation.
Since warm water holds less oxygen, the summer months are the most vulnerable to a pond and the fish it contains and the reason for this is merely water remains at a warmer temerature than air. At night the air temperature cools down the water remains warm and the fish are still in the demand for the oxygen. During the day plants produce oxygen and release it into the water via the process of photosynthesis thus keeping a good additional level of oygen for aquatic life. Now at night plants do not have the sunlight to produce the oxygen and they therefore start to absorb the oxygen they release during the day and start to release carbon dioxide. So as you can now picture the plants are not really adding anything to your pond water for the fish as what they produced during the day they will use up that night. The only source of oxygen production at night would be from your pumps and air pumps, Turn those off at night like many do and you can understand why the fish will suffer oxygen starvation and sadly die. Other factors to remember are, accumulated organic matter , uneaten food or faeces will also reduce oxygen levels and should be removed from the pond via the general maintainance you carry out such as using a pond vacuum.

A common myth is that a sturgeon will die because of a thunder storm, Granted this is a partial myth as it is not the actual thunderstorm that killed the sturgeon but infact the lower atmospheric pressure during thundery humid weather reducing the amount of atmospheric oxygen level per unit surface area of water. The sturgeon would have died from lack of dissolved oxygen in the water, keep those pumps and air stones running at all times.