Questions & Answers
Should I have rocks, stones, or gravel in the bottom of my pond?
Rocks and stone in a pond may make your pond more natural looking and certainly provides surface area for natural biological filtration and the growth of helpful flora. Each pond is as individual as the people that operate them. Some are primarily for water gardens, and a few gold fish, and others have little or no plantings and heavy fish loads. The potential drawback with rocks in a pond is that the spaces between the rocks are where mulm and debris will naturally go, and as it accumulates it will eventually cause areas of decay without oxygen, which causes "anaerobic bacteria" to grow. These types of bacteria have often been associated with very harmful problems causing fish disease and death.
If your choice for your pond is to have a showplace for fish, our club is of the opinion that unless you are willing to do significant work to remove the accumulation from between and under the rocks, it is best to keep rocks to a minimum. Most "pros" believe that the disadvantages far outweigh the advantages of in-pond rocks and gravel. Reasons: Rocks with sharp edges can injure the fish and gravel is a collecting point for unwanted pathogens, parasites, harmful bacteria, rotting debris, etc.