Stocking a pond can be done hastily and without much thought, or it can be done meticulously with a good deal of forethought and planning. Just like anything else, the more thought you put into it, the better results you generally can expect to get. Today I’m going to let you in on a couple secrets that many fish sellers won’t tell you for fear of losing a sale.
Pond Secret #1: Grass carp can cause more problems than they fix when stocked into recreational fishing ponds. I bet that’s the first time you’ve heard of a fish seller trying to talk you out of buying fish, huh? Here’s the thing about grass carp: they eat things other than just vegetation. The owner of a prominent fish hatchery in the northeast asserts that they will eat invertebrates and fish fry, and this is consistent with our experience. But this isn’t the biggest problem with those submarines.
Grass carp not only will readily consume pelleted fish food intended for other species such as bluegill, catfish, or feed-trained bass: they relish it, and in the presence of it will focus on it above all other food sources, including that primrose or watermilfoil you stocked them to eat. And, once they get to be about three feet long, their affinity for that expensive fish food you’re intending for your gamefish has grown to the extent that they will physically bully your bluegill and bass away from the pellets so they can hog all of those tasty morsels to themselves. They roll their bodies and slap their tails – and what 9″ or 10″ bluegill is going to stand up to a 36″ carp that weighs thirty times as much as it does? It only takes a handful of big grass carp to utterly wreck the most careful management plan, and once they’re in your pond, short of hiring a bowfishing expert to get them out for you, you’re stuck with them for ten to fifteen years at a minimum.
Another key detail about grass carp that most fish sellers omit is that they have preferred, and non-preferred, plant species. Multiple studies have confirmed this; for example, one study found that white amur would not consume lily pads even in the absence of other vegetation types. Filamentous algae, far and away the most common aquatic vegetation found in freshwater ponds in this country, is not one of their preferred foods, and they will only consume it in the absence of all other vegetation types.
If your pond is a subdivision pond and your primary or only concern is keeping it free of weeds, and you happen to have a species of vegetation that white amur have a taste for, they’re a great biological option and relatively low-cost compared to herbicides. If on the other hand you have a pond for which fishing is the primary purpose, think twice before stocking grass carp.
Pond Secret #2: Channel Catfish will wreck a trophy-bluegill pond. If you have followed my business for any length of time, you know that we specialize in trophy bluegill. Lots of pond companies say they can grow big bluegill, but few have actually put in the time to study what it takes to produce a pond where the bluegill average close to 10″ and there are numerous two-pounders. One of the things we have learned over the years is that channel catfish eat fish food pellets with a zeal rivaled only by grass carp. They will literally open their mouths and swim along the surface in a zig-zag pattern among your high-dollar pellets, vacuuming them in by the dozens as your bluegill watch haplessly from the edge of the pellet area. Like white amur, channels get larger by the end of their first year in your pond than most bluegill will get in their lifetimes, meaning they reach a size early on that allows them, like the carp, to bully your other fish away from the pellets and keep them mostly to themselves. And when they’re not eating pellets, they readily consume all of the same natural foods as your big bluegill, namely invertebrates, fry fish, and crustaceans.
But channel catfish are not just bad in bluegill ponds. They are predators, meaning they will take food away from your largemouth, and in significant quantities once they reach three pounds (which they can do in one year in ideal conditions). The diet of adult channel cats has been found to consist of up to 86% fish – meaning they are aggressive competition for your bass for forage.
Channel cats are also notoriously hook-shy. This trait has been widely observed among fisheries biologists, to the point that these days many knowledgeable pond pros will recommend against stocking channels, even in small numbers. And this trait is magnified as the cats get larger, meaning when they get to the point that they’re doing the most damage, i.e. eating greater quantities of your fish food intended for other species and more effectively and thoroughly scaring the other species away from the food, that’s when they also become the most difficult to entice onto a hook – even with live or stink bait. Fisheries biologists have documented the entire population of channel catfish in a pond turning off to all angling presentations for hours after just one of the population was hooked, and this is consistent with our experience of the fish. To have any kind of reliable fishing for channels, you have to stock high numbers of them such that they’re crowded and competing for food resources; and when high numbers are stocked, you can completely forget about any species other than the catfish getting any of those pellets. And, channel cats have even longer lifespans than white amur: their average lifespan is generally given as fourteen years but they have been known to live up to forty years. Forty years is a long time to have a big, problem-causing fish in your pond.
If channels are your favorite fish, by all means stock them; if on the other hand trophy bluegill are your goal, keep the whiskers out of your pond.