Keep Pond Dye out of Your Tennessee Pond
Imagine you’re a bird lover, and you just bought a house with a good-sized back yard. You’re excited about the possibility of birdwatching on your very own back forty. So of course the first thing you would do to attract the maximum number and species of birds would be to cut down all the trees, bulldoze off all the grass and any flowers the previous owner may have left, put down a layer of gravel, and lastly, set out a couple bird houses on the ground. Sounds like a great plan, right?
No one would do that, because you don’t have to be a bird expert to know that birds need an ecosystem to live in, and trees and grass are fundamental parts of said system, as are flowers. Guess what? If you put pond dye in your pond, you’re bulldozing away the grass and flowers and trees - you’re eliminating the ecosystem. Water by itself is not an ecosystem for fish any more than air without trees or grass or flowers is an ecosystem for birds, squirrels, and the many other creatures that will use such a system. And water without an ecosystem will produce very pitiful fish.
There is indeed much information available online instructing pond owners to apply dye to their ponds. There also are multiple large companies working in this very state who regularly advise their customers to put dye in their ponds. One thing all of those companies have in common, besides caring more about their wallets than the best possible outcome for your pond, is that they all hail from states north of us. Pond dye is widely used by knowledgeable pond consultants up north, and it has a purpose there; it doesn’t have a purpose in your Tennessee pond if you care at all about the fish and are not just using the pond as a water feature.
Pond dye has one use: to limit bottom-rooted aquatic plant growth in a pond. It does this by blocking sunlight from penetrating to the pond bottom, where most aquatic plants begin their growth; because all plants have to have sunlight for photosynthesis, they die when they don’t get it. Dye won’t do anything at all to plants that float on the surface, such as duckweed and watermeal; but it will limit the growth of most aquatic plants that start their growth journey in the sediment at the bottom of the pond.
You might ask why stopping the growth of plants in your pond is a bad thing. There are indeed many pond managers out there who would have you believe that all aquatic plants are bad; they’ll tell you to stock grass carp even in a brand-new pond that has zero growth; they’ll tell you to use pond dye. This all makes perfect sense if you believe birds will flock to a yard comprised of gravel and nothing else, and thrive there; if you believe animals need an ecosystem to flourish, you’re not going to give your birds the gravel yard, and you shouldn’t give your fish the equivalent, which is a pond with no plants or phytoplankton. Aquatic plants are nature’s habitat for fish. There’s a reason that bass fishermen get angry at the government when it starts killing all the aquatic plants in their favorite reservoir: because they know the bass fishing is about to go downhill.
Dye doesn’t just kill macrophytes, the plants large enough to see; it also kills phytoplankton, also known as planktonic algae, the microscopic plants that live in the water column and give water its green color.
Phytoplankton isn’t an optional accessory for a pond or lake’s ecosystem - it’s a necessity. Phytoplankton are the foundation of the entire food chain in any water body, whether one is talking about a pond or the open ocean; no phytoplankton, no life. All fish rely on phytoplankton as food, some directly such as filter feeders like shad or paddlefish or whales, and some indirectly by way of eating things that eat phytoplankton. Aquatic invertebrates eat phytoplankton; zooplankton, the microscopic and macroscopic bugs that swim around in the water column, eat phytoplankton. All fish in the fry stage consume zooplankton, and many species consume zooplankton as adults, including bluegill.
If you were interviewing a pond consultant towards potentially hiring him or her to work on your pond, and the first thing he said to you was that you needed to kill the food chain in your pond, would you hire him? Of course you wouldn’t. Guess what? Any consultant who tells you to use dye on a Tennessee pond is telling you exactly that.
One of the catch phrases thrown around by dishonest pond companies these days is “nutrient management”. Nutrient management can indeed be important if you own a private lake in Florida that used to be a phosphate mine and your lake becomes so choked with weedgrowth that you can’t pilot a boat through it; but most private ponds and lakes in this state do not ever get weedgrowth at that level unless they were improperly constructed (that’s a blog post for another time). And even those ponds, with some basic management, will never need the fish-harming use of dye.
Monthly fertilization from March through September or October is a staple management technique that has been widely recommended all across the South, here in Tennessee and in every other state, for many decades. There are entire chapters devoted to pond fertilization in the pond management literature from TWRA, Auburn University, the University of Georgia, Mississippi State University, the Kentucky Department of Fish and Wildlife Resources, University of Arkansas Pine Bluff, South Carolina Department of Natural Resources, and even the Florida Fish and Wildlife Commission. Why then are these consultants from northern states never even mentioning it to you? Why do they talk to every pond owner only about “nutrient management” and tell you that nutrients are always bad?
Because they come from states where fertilization isn’t widely utilized, and they’re too lazy to adapt to this climate, and too greedy to tell you that they don’t understand southern ponds like someone who’s actually from here does. Fertilization is purposely adding phosphorus, which is the nutrient always targeted by “nutrient management.” Pond fertilization is the opposite of what the nutrient management folk are telling you to do. And every authority in this region will tell you that it’s good for your pond, and that most ponds need it.
Pond dye is widely used on ponds in northern states because too much phytoplankton in a pond when the pond ices over can lead to a fish kill. A pond in northern Ohio may be completely covered in ice for months at a time; once snow covers the ice, it stops sunlight from penetrating into the water, and any phytoplankton present in the pond will die. All plants remove oxygen from the water as they decompose; if a large enough biomass of plants dies all at once, it can remove enough oxygen from the water to cause a fish kill. Phytoplankton are the primary producers of oxygen in a pond that is not aerated and doesn’t receive significant wind action; so when phytoplankton die, production of oxygen ceases, and what oxygen is already present gets used up in the decomposition process.
I have twenty-five years of experience managing ponds in Tennessee; that experience actually dates all the way back to 1987, when I was a junior in college and began working with other people’s ponds as a way of having better places for myself and my grandfather to fish. In nearly forty years of climate change and getting to see thousands of ponds in this great state across two stints (I lived in California from 1997 to 2007), I have never come across a single pond that stayed iced over long enough to have a fish kill. It’s rare for any pond in this state to have ice for more than a week or two at a time, and usually when we get that cold, we don’t get snow.
So you aren’t saving your fish from certain death when you put pond dye in your pond. But you most certainly are bulldozing away all the grass and flowers and trees and making them completely dependent on whatever food you may toss into the water, for their survival. And any pond consultant who actually knows something about fish will tell you that if you’re trying to grow the biggest possible fish, you can’t do that just with pellets: your fish need the natural food chain, or they won’t come close to their maximum obtainable size.
And because pond dye kills phytoplankton, it not only takes away the food chain, but it takes away oxygen, as surely as does ice on the pond surface. More than once I have worked on a pond where another company had just applied pond dye, only to have it cause a fish kill. Not one of those companies ever admitted their mistake to the customer, either. And they certainly didn’t offer a refund - because your money is all they care about.
Pond dye is easy; so are grass carp. They’re both easy ways to make a pond look like a swimming pool. And landowners who don’t read this blog and don’t do their research have no idea that they’re being cheated; they have no idea the caliber pond they could have with real, knowledgeable management. If we manage your pond for you, you may have to do more work to control the aquatic plants than you would with some other company; but your fish will be bigger within three years of when we set foot on your property than anything you’ll ever dream of seeing with the landscaper consultants.
