Hello Everyone, I have a 3-acre pond in New Windsor NY. It is naturally spring fed from an underground spring and has a runoff on the west side that is constantly flowing. The pond is stocked with Big mouth Bass, Koi Fish, Blue gill, Catfish, Snapping turtles, painted turtles, and I have seen a bunch of other unidentified species. The pond has a 6 nipple aerator system and 3 large fountains that are used for underwater and surface aeration. The main issue I seem to be having is improving water clarity so people can see the koi fish while they are being fed. Every year I add beneficial bacteria to help with water health. I have also dredged the pond to remove the muck but after multiple attempts to remove large amounts using a dredge, I still have a lot of muck.
I understand that achieving perfect water clarity may not be possible or even good but if I can clear the pond a little more it will keep everyone else happy.
The Koi are a carp species. They stir up the bottom when feeding naturally, and muddy the water. If you want to keep the Koi, you will have at least somewhat muddy water.
Is your pond mostly ornamental? Is there any fishing allowed?
One problem may be too many fish! As the fish (all species) grow, some must be culled to maintain adequate space in your pond.
Further, if people feed the koi, then there is a huge buildup of nutrients in your pond ecosystem. Even if your beneficial bacteria is helping breakdown the muck, those nutrients are still in the system.
You probably need to pull some sample jars to determine exactly what is causing your murky water.
It could be actual silt/sediment stirred up by the fish. It could be blooms of phytoplankton (algae) and zooplankton. It could be clay particles suspended by their electrical charges. (There is a treatment for that condition, that will not harm your aquatic creatures.)
Looking at your pics, have you considered adding some floating islands? (There are some good threads on Pond Boss.) The plants on the floating islands will use up some of the excess nutrients in your pond and make less available to the algae. Further, the turtles like to loaf on the islands - and the people that like turtles would probably get some enjoyable photos.
Six main things are going on in your pond to create the majority of the water turbidity. 1. Koi are morphologically the same and identical to all the body structures of common river carp (German imports) except the Japanese have breed this sub-specie or variety to have colorful body markings.
2. Koi and common carp feed by digging or rooting into the sediment for gathering bottom oriented foods - they are omnivores. They have no stomach thus they cannot binge feed and rest for long periods between feedings. Koi-carp feed and root in the sediments many hours a day to keep food moving through their intestines for growth and nutrition. Rooting in the sediments produces a cloud of roiled sediment up around and behind the fish. I have watched koi feed and dig into the sediments clear up to their eyes.
3. Aeration methods are designed to move water and keep it moving for circulation. Circulating water currents helps keep very tiny sediment, silt, and detritus suspended into the water column - cloudy - turbid water. Most of the sediment and detritus particles in the water column will be 0.1 to 50um sizes - very slow to settle to the bottom. see #7
4. Bottom rooting activities help keep bottom sediment nutrients, organic decomposition particles and clay-mud particles resuspended into the water to stimulate more growths of decomposition bacteria and phytoplankton in the water column - both of these add to the reduction of water clarity. As noted feeding the fish always adds fertility directly or indirectly to the pond. More fertility causes more plants to grow. In your case the plants are tiny phytoplankton that when abundant often gives the water a green or brown hue.
5. The small catfish-like fish in one of the koi pictures look to me to be bullheads. Bullheads are also bottom feeding and sediment disrupting types of fish. True catfish have forked tails and bullhead tails are rounded, Some angling with worms on the bottom should allow one to catch a few and determine if catfish or bullhead. Large catfish will also disrupt sediments but not as much compared to bullheads.
6. All these activities of bottom feeding fish keep natural submerged vegetation from growing in that they are eating it or keeping it from getting established. Submerged vegetation usually does a good job of reducing (nutrient absorption & competition) the amount of bacterial and phytoplankton growths and plants tend to cause suspended sediments to settle onto the bottom. Almost always ponds with good amount of submerged plants have clear water.
7. Generally during winter when the bottom rooting fish are more dormant due to cold water, they feed less and water in winter is usually the clearest compared to warmer water temperatures when all the fish noted above are most active.
Last edited by Bill Cody; 04/22/2309:34 AM.
aka Pond Doctor & Dr. Perca Read Pond Boss Magazine - America's Journal of Pond Management
What may partially help is to use traps to catch as many of the bullheads as possible. Remove every last one you catch. Try to fence off an area with netting to exclude as many fish as possible from that area and try to get underwater plants established there, even Eurasian Water Milfoil. It's an invasive, but can, once established utilize many nutrients to help clear the water. Try to do that on the upwind side of the pond. Then look into doing an aluminum sulfate treatment to the pond, that should help strip out even more nutrients.
Remove every Largemouth Bass that you can that is over 15"-16", that will allow more of the smaller LMB room to grown and in doing so they will consume more of the smaller fish.
Run a trotline daily baited with hot dogs, chicken livers, etc (not worms) to catch even more bullheads.
