Tootsie, is your pond a valley pond or have a lot of ground draining into it ?
Another thing is that from what I hear bullheads are bottom feeders and keep the mud stirred up, and probably at high populations also keep the bottom devoid of plant life which produces O2 and use up available nutrients. That along with the low light levels at the bottom caused by the muddy conditions, again, caused by the bullheads makes me think that there is no photosynthesis going on except some plankton, and that is pretty much zero in winter.
My theory is that Bullheads are a river fish that always have a supply of fresh water coming down stream. They make their living digging around eating clams,crayfish,worms and the like. the population is kept low by predators and the water is usually ice free and moving.
When you put fish in a pond they are WAY more dependent on bottom dwelling plants for water quality of all kinds.
Just like we are dependant on the plants and ecosystem built upon them as we make our living on the bottom of the pond we live in, the earths atmosphere.
Just like the humans that over populated Easter Island and nearly completely destroyed EVERY living thing in their little pond, including themselves, your bullheads have overpopulated their pond and destroyed their ecosystem.
Just like we are doing to ourselves now. And we WILL suffer a similar fate, if we don't stop. NOW !
Fish don't know any better. They just know that the food is running low and that they better dig more, looking for more food, no plants can grow, and the cycle of death begins. Just like here with our mountain top removal coal mines.
I hope we are smarter than fish. But I don't think so.
The solution is to kill off all or most of the population and keep the population low. The fish I mean.
The other thing is that the ecosystem must be restored. Restored by the continued VERY low or no population of plant eating fish. You can't put your cows on a newly plowed and seeded pasture ! You have to WAIT until a plant based foundation for the ecosystem has grown up thick before you add your carefully controlled population of fish or cows. Otherwise disaster is looming.
If it where me and it were my pond I would be like God during Noah's time. I would put my koi in an ark and I would drain that pond and kill every fish in it and start over. If I had the money I would hire someone to clean it out and enlarge and improve it, and when it refills I would quickly plant the most desirable bottom dwelling and shallow water plants as thickly as possible.
The best thing to plant is Sago pond weed. It doesn't grow more than 3 ft tall from the bottom, has lots of very fine soft leaves on a soft plant and out competes most other objectionable surface sprawling plants and algae and keeps the water clear and photosynthesizes all winter because it's evergreen. and it's native. It appeared in a friend's pond and I transplanted it into all of my ponds and I love it. Water lilies also have no problem with it and eventually shade it out and take over.
Also it should make LOTS of food for a few koi,and it's great for ducks because it makes lots of seeds and is great for all of the life forms in your pond like dragonflies etc because they have food and shelter from predators.
one of the best shore line-shallow water plants is Eleocharis Montevidensis-Spike Rush, mixed with the other Eleocharis species like Chinese water chestnuts and square stem rush. Also red stem ludwigia- Water purslane. And also Creeping Jenny. Peppermint and spearmint are also great but peppermint will get thick sometimes, but if you grab it it pulls out by the finger tips because it grows hydroponically with no roots in the mud. once you thin it it settles down and grows mixed with everything else without being a bully.
These plants will grow together and totally prevent cattails from starting or control the spread of a small patch that can be held at bay very easily by biannual pulling.
I could sell or trade all of these plants to people that are starting a new mud pond, or renewing an old pond but I usually don't have much time for that kind of thing, but if anybody's interested in that sort of thing you could probably talk me into it. I might post something in the aquatic plants trading forum next spring.
Another plant that I like is Italian Vallisneria, the small spiral leafed type that's about 8 in tall. It carpets the bottom like the most beautiful green grass and is green all winter in zone 6b. West Virginia. It's not native but I like it allot.
It's hard to get going because it doesn't make seeds and spreads slowly so I use a snorkel and mask and plant it all over. It might not be able to compete with Sago
A well balanced mud pond does not need a bubblier or ANY money. Once it's built and planted.
Believe me I know. I have acres of beautiful mud ponds with high fish populations that freeze over most winters and never a dead fish. My fish are over populated because I don't have any predator fish like bass. They are Shiner minnows, fish bait, up to 11 in. long that I plan to sell for fish bait. That's why no bass.
I have no bubblers or money draining power lines.
A well balanced mud pond is a beautiful thing for fish and human.
