Fish emulsion is a great fertilizer for plants. A small backyard pond is a miniature representation of the natural aquatic world. If you have fish in your pond, you have a source for a great fertilizer for your plants. However you do not want to remove too much or you could offset the balance of your pond.

There are two groups of elements in a garden pond. Those that enter the air and those that accumulate in the pond and cause problems such as algae. A closer look at these elements will give you a better idea of what exactly is in pond water and why fish emulsion makes such a great fertilizer.

Nitrogen – Essential for a Healthy Aquatic Environment

Nitrogen is essential to a health pond. It is created by beneficial bacteria which reprocess the various nitrogenous compounds. These compounds can be found on both soft sediment and on all of the hard surfaces inside a pond. Nitrogen gets into a pond through leaf matter, fish food, nitrates in untreated tap water as well as proteins from snails and worms.

Phosphorus – a Reactive Element

Phosphorus enters the pond environment when fish eat live plants because phosphorus is incorporated into plant tissue. When the fish excretes the excess phosphorus that is not absorbed by the fish’s body is released back into the water. Phosphates can also enter the water through fish food and tap water. Phosphate levels are generally pretty low in a backyard pond however they do promote the growth of algae in a pond.

Oxygen and Carbon Dioxide

When oxygen and carbon dioxide are created in a pond they are released back into the atmosphere when there is too much in the pond water. Oxygen is produced by aquatic plants through photosynthesis and is beneficial to the plants and animals in the pond as well as the environment as a whole. Carbon dioxide can occur in algae rich mud as well as a heavily fed pond, even if the water is clear. A low pH can mean there is a buildup of carbon dioxide. However, this is usually short lived and the excess will enter the atmosphere. If there is a constant supply of too much carbon dioxide it will need to be offset by the addition of more oxygen so that the aquatic plants, fish and other critters in your pond do not suffer from oxygen deficiency.