If you have fish in your pond, you want to keep them healthy. One thing that can cause your fish to die unexpectedly is stress caused by lack of oxygen. Fish need oxygen, just like we do. But instead of absorbing it from the air, as we do, they absorb it from the water. If the oxygen level in the water is too low, then the fish can get stressed and die.



Algae can cause a lack of oxygen in two ways. Algae produce oxygen during the day. At night, this oxygen is absorbed from the water by the plants in the pond. If there is a large quantity of algae in the water, then plants will quickly deplete the oxygen at night, leaving none for the fish. If the algae dies suddenly, either naturally or through the use of an algaecide, this can cause a loss of oxygen, since the algae are dead, and no longer producing oxygen. The decomposing algae can also further deplete oxygen from the pond.

If you have a lot of fish in your pond, then the oxygen level in the water may be just enough for the fish. If there are any further claims on the oxygen supply, then the delicate balance will be thrown off. When the water starts to warm, it cannot hold as much oxygen as cold weather. If you do not have sufficient aeration of the pond, then things can quickly get critical. When the weather warms up, a small fountain or waterfall may not suffice to keep the water sufficiently oxygenated. As the water warms up, you'll need to provide more aeration to keep your fish from dying.

The only way that you can measure the oxygen levels accurately is with testing devices. For the average person keeping a pond, these testing devices may not be on hand. The easiest way to ensure that the pond has sufficient oxygen, is to provide generous and continuous aeration. Diffusers and airstones, along with an air pump will bubble air into the water, and help to maintain the oxygen at sufficient levels. Get a small electric air pump, and run some tubing to the airstone, and place it into the pond. If you have a large pond, you may need more than one airstone.

Other ways to get oxygen into the water are through waterfalls and fountains, which churn up the water, adding oxygen. If you plan on having a waterfall flowing into your pond, you should make sure it is large enough to aerate the water. If you already have a waterfall, it may not be feasible for you to enlarge it. In this case, an extra pump and a fountain or two will provide aeration for your pond. You can find fountains in different sizes, with various spray patterns. In addition to providing oxygen for the pond, waterfalls and fountains have the added advantage of providing the soothing sound of falling water. You get to maintain oxygen levels, and relax to the sound of falling water... Sweet!

If you're going to have fish in your pond, it's your responsibility to keep them healthy. If you ensure that they have plenty of oxygen, the fish will be happier and healthier, and they'll be around for you to enjoy for a long time.