Backyard ponds add elegance and style to the landscaping throughout your property. Watching water and fish provide a calming effect after a long, hard day. It helps you remember the reason you work so hard. Occasionally, you may find yourself relaxing and watching the water, only to realize your fish are still tiny minnows or have diminished in number. Here are some common reasons the fish in your pond suffer from a failure to thrive.
1- Too Many Fish in the Sea
After building or reclaiming a pond most people cannot wait to stock it with fish. Koi are one of the most popular varieties for stocking in backyard ponds or ornamental ponds. Many folks feel that if 10 fish make their pond attractive and serene, then 25 koi will be even better.
This could not be further from the truth. Too many fish in a small pond will not grow properly because they will not have enough room to grow. A good rule of thumb is to have no more than one inch of fish per gallon of water. That is the maximum number of fish a healthy pond can support. Your koi are only as healthy as your pond.
2- Limited Food Supply
In Mississippi, small farm ponds see a common problem. According to the Fish and Wildlife Department, plenty of small bass exist in these small ponds. They range in size from eight to 14 inches, they have an extremely slow growth rate and they die before reaching a normal size. Like all other creatures, bass breed to propagate their species. If your pond is large and deep, then it can handle the bass originally stocked.
Their breeding produces offspring well within the limits set by the area of your pond. Bass competing for limited food in a small pond are doomed to never grow larger. The only solution is giving more food, which is awfully expensive, increasing the pond size, which is often not possible or reduce the number of fish competing for food in your small pond.
3- Nutrient Poor Ponds
Fish excrete waste products, just like other creatures. Your fish depend upon the water surrounding them for survival. Fish waste has a high ammonia content that leads to dangerous nitrogen buildup. Algae thrive in nitrogen-rich environments, however, fish do not.
Plants that grow above and below the water decreases nitrogen levels and provides food for your fish. Lily pads discourage algae and provide shade for your pond. Plants increase water oxygen levels and give fish a place to play and hide. They also create a nutrient-rich environment for your fish.
4- Shallow Ponds
Shallow ponds tend to produce slow-growing fish with stunted growth. Few natural resources grow in shallow ponds which encourages algae growth. Algae decrease the water oxygen vital to a healthy fish. If you want healthy fish that grow properly, then follow USDA guidelines and
Create a pond that is at least eight or more feet deep and covers over 1,000 square feet.
Pesticides, herbicides and harmful runoff are deadly to a shallow pond. Soon you find yourself with a pool of standing, stagnant water where mosquitos breed. Ideally, a pond a least eight feet deep will contain deeper areas where fish can forage in the mud and congregate during the hottest parts of the day.
5- Genetics Limit Great Expectations
A lot of people believe the myth that fish grow to the size of their environment. While it is true that their environment can inhibit their growth, there is no truth to the belief that huge ponds allow your fish to expand their growth indefinitely. As with all of nature’s laws, genetics normally dictate the size of the offspring. If koi are your preferred pond fish, their normal genetic makeup limits their growth to a length of about 18 to 26 inches.
You may consider this small because you have seen larger koi. Keep in mind that 26 inches is over two feet in length and that is before considering the diameter of the koi. A 26-inch full-grown koi tends to be exceptionally large indeed. Consider the environment where you may have viewed koi you feel grew larger. Likely the circumstances under which you viewed the fish took place within a building or area that had small features that made the fish appear huge in size.
6- A Change in Environment Causes Growth Spurts
Sticking with koi as your pond fish of choice brings up the next reason you do not see growth in your fish. Fish like koi emit a growth inhibitor or pheromone naturally much of the time. During times of stress, your fish increase the amount of growth inhibitor put out depending on overcrowding and competition for food. A big factor affecting this growth inhibitor is how often the water washes it away.
In ponds where there is continuous water flow providing fresh water for fish this growth inhibitor quickly washes out with the change in water and fish grow far more quickly than in a pond where water changes occur regularly but only on a weekly basis. Technically, changing the water in your pond weekly is adequate. However, if you want to see regular growth while your fish mature to their full size, you should change your pond water quite often. Preferably, your pond has a system to continuously circulate fresh water to keep both your pond and fish in good health.