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How to Ruin a Trophy Bluegill Pond, or: Beware Snake-Oil tilapia sellers

So I have been debating for months now on whether to make this post; and then just today I saw a tilapia dealer making simply false (and harmful) claims on another website. This person claims that tilapia are the “magic bullet” of pond management in Tennessee; he claims, among other things, that they take no oxygen away from your other fish, and that they will make all of the fish in your pond bigger. Let me tell you a story about a pond.

Our Trophy Bluegill Tennessee Pond Management Story

I have two arms to my small business: the pond management side, through which pond owners pay me to improve their ponds, through fish stocking, weed control, aeration installation, yearly management plans, etc.; and the guided-trips side, through which anglers pay me to put them on trophy bluegill. For the latter, I spend my own money on the intensive management of several ponds. In March of 2011, I stocked a one-acre pond with 200 3-6″ and 50 6″+ coppernose bluegill from Overton Fisheries in Buffalo, Texas; two months later, I stocked the pond with approximately 700 fingerling coppernose from a hatchery in Alabama. In April of 2012, in three hours of fishing, I and the landowner and his son caught half a dozen 10″+ coppernose that would have gone between sixteen and nineteen ounces each. These fish were two years old; every one of them eventually would have made two pounds, and probably several would have made three. The coppernose that I had stocked as fingerlings a year before were already averaging 8-9″, some of them twelve ounces or better, at one year old. By all rights, that pond today should be one of the best bluegill ponds anywhere – and it would be the centerpiece of my guide business.

But said pond is an old, eutrophic pond, and has had bad watermeal ever since I began working with it. I installed an aeration system with three diffusers two years ago, and, though aeration normally makes a tremendous difference, it barely fazed the weed. This pond is completely surrounded by trees and gets a heavy load of new decomposing matter every year; it also has steep banks, and receives little wind. As of mid-May last year I had already spent over $400 on Whitecap with no effect, and I was desperate to get the watermeal under control.

Tilapia are touted as a biological control option for watermeal. Every time I had ever seen a pond or lake stocked with them, the bluegill had overpopulated that same year; but this particular pond has a large population of stunted black crappie in addition to a good population of young bass, and I thought that if ever there were a pond with enough predators to keep the bluegill from overpopulating after tilapia were stocked, this pond would be it.

Don’t get me wrong: I’m a pond management professional, and I fully accept my responsibility for the decision to stock the fish: I should have known better. But I decided in part to stock them because there are tilapia dealers out there who claim that tilapia improve the health and growth rates of every fish in the pond, all species; and I know that some small part of me believed it.

I stocked fifty pounds of tilapia into the pond, the low end of what’s recommended for weed control (or even for forage, going by the recommendation of some prominent pond management companies). The effects were devastating to my prize coppernose immediately. Whereas before the tilapia were stocked, every time I went to the feeder on that pond I would see dozens of huge coppernose, within two weeks of stocking the tilapia, the aggressive newcomers had bullied away the big bluegill, and when I approached the feeder I would see fifty to a hundred tilapia a few inches beneath the surface, waiting on pellets. They didn’t control the watermeal, but they sure took away food from the fish I was trying to grow.

But that was far from the worst of it. Tilapia are stocked by many pond and lake owners because of their fecundity: they spawn even more heavily than bluegill. And, contrary to what some tilapia dealers would tell you, any fish in your pond takes up oxygen, and the more fish you have in the pond, the more demand there is for oxygen. I drove up to my best pond one day last August to find the ultimate gift those tilapia had given me: dozens of pound-plus coppernose floating dead, all up and down the bank of the pond. The tilapia survived, of course; they can tolerate lower oxygen levels than most fish.

The small bluegill also survived; small fish take less oxygen than big fish. Now the pond is full of 2-5″ coppernose, so much so that I had to take remedial action in the form of stocking fifty 6-8″ largemouth and ten one- to three-pound blue cats. But it will still take a minimum of two years to get the pond back to where it was, if I can even do it that quickly.

Lest anyone suggest the watermeal caused the fish kill, the tilapia did keep it from completely covering the pond; on average, the pond stayed about twenty-percent covered on any given day. I had grown bluegill and bass without a hiccup the year previous with the same amount of weed cover, simply by aerating. Now, a year too late, I’ve learned that the generic brands of flouridone such as Whitecap are now made overseas and have quality control issues; that same pond is completely clear of watermeal and has been for over a month thanks to Clipper.

Tilapia are not the worst thing to do if you’re trying to grow trophy bass, and you have unlimited funds to spend. They’ll provide a boost to the overall quantity of forage in your lake or pond. But if trophy bluegill are your goal, avoid tilapia like the bluegill plague that they are.