The US Lakes Where Fish Are Unsafe To Eat

In Dutchess County, New York, health officials tell anglers not to eat a single fish pulled from Fallkill Lake, no matter the species or size. It is one of a growing number of American lakes where the water looks fine but the fish carry a warning. Contaminants such as PFAS, mercury, and PCBs build up in fish over years, and the people who eat those fish regularly take on the same load. Every state has issued consumption advisories of some kind, and the lakes below rank among the most specifically flagged in the country. Before keeping a catch to eat, it pays to know which fish local agencies have flagged and why.

Why Fish Become Contaminated

Fish take in pollutants from the water around them, the sediment below them, and the smaller organisms they eat. Those chemicals collect in the body over time through a process called bioaccumulation, and larger predatory fish reach even higher levels by eating smaller contaminated ones. The three contaminants behind most advisories are PFAS, mercury, and PCBs. PFAS, the so-called forever chemicals, are human-made compounds used in stain-resistant fabrics, water-repellent goods, and firefighting foams.

PFAS persist in the environment for long stretches, and some types, including PFOS, settle into the edible parts of a fish where normal cooking or cleaning will not remove them. Mercury enters waterways through pollution and converts into methylmercury, a highly toxic organic form. PCBs, banned in the United States decades ago, still sit in lake sediment and collect in the fatty tissue of fish, especially bottom-feeders such as catfish and carp.

Fallkill Lake, New York

Fallkill Lake in Dutchess County carries the bluntest warning in New York's advisory system: eat none of it. In 2025, the state Department of Health issued a blanket recommendation against eating any fish species from the lake because of extremely elevated PFOS levels. The guidance updates each year, and PFOS, one of the most common forms of PFAS found in fish, drove this listing alongside longstanding concern over mercury and PCBs. Fallkill Lake and the connected creek both fall under the advisory, so there is no size or species that clears the bar here. For anglers used to reading advisories as a set of limits, a total do-not-eat listing is the signal that lab results came back well past the usual thresholds.

Lake Mahopac, New York

About twenty miles south, in Putnam County, Lake Mahopac is where the advice gets more granular, with some fish allowed and others ruled out. The New York State Department of Health does not close the whole lake. Instead, state guidance names three species whose largest fish are off the table. The advisory recommends against eating walleye longer than 19 inches, smallmouth bass over 15 inches, and northern pike longer than 26 inches, since the biggest, oldest fish of each species hold the most accumulated PFOS. Smaller fish of the same species come with meal limits rather than an outright avoid. The lesson at Mahopac is that size matters as much as species: a keeper-sized walleye and a trophy one can fall on opposite sides of the warning.

Echo Lake, Texas

Echo Lake, a small urban lake in Tarrant County near Fort Worth, has carried a warning since the Texas Department of State Health Services tested its fish and found a mix of long-lasting industrial chemicals. The contaminants of concern are PCBs, dioxins, and dieldrin, a synthetic insecticide, all of which collect in fish that feed near the bottom or eat other contaminated fish. Common carp are the worst affected, and state health officials advise that no one eat carp caught here at all. Largemouth bass carry unsafe PCB levels too: adults are told to limit bass to one meal a month, while children under 12 and women of childbearing age are advised to avoid Echo Lake bass entirely. The current advisory replaced an older outright ban on possessing fish from the lake.

Kent Lake, Michigan

Kent Lake, an impoundment of the Huron River in Oakland County, is the reason a long stretch of that river now sits under a Michigan "Do Not Eat" advisory. Testing in 2018 found elevated PFOS in every fish filet sampled from the lake, which prompted the state to warn against eating any fish from a run of the Huron River and its connected waters, Ore Lake among them. Investigators tied the PFAS to industrial discharge upstream, including chrome-plating and other manufacturing linked to the Wixom wastewater plant, and the chemicals do not break down in the water for years. Trimming skin and fatty tissue reduces some contaminants, but PFOS lodges in the muscle, so cleaning and cooking will not make these fish safe. Michigan officials note that swimming and boating on Kent Lake remain fine, because the risk comes almost entirely from eating the fish.

Lake Erie

Lake Erie is vast, but size is no guarantee that a given fish is safe to eat, and it stands in here for the wider Great Lakes picture. Erie has the same long history of industrial pollution as Lake Ontario and the others, including chemical waste, heavy metals, and nutrient runoff. Advice varies by species and size rather than shutting the lake: the biggest walleye, generally those past about 25 inches, get held to roughly one meal a month because of PCB and mercury buildup, while smaller walleye and yellow perch stay closer to a weekly allowance. Bottom feeders such as carp and catfish draw the most caution, since they take in contaminants straight from the sediment. State agencies lean on these size-and-species limits so anglers can keep eating the safer fish while cutting their exposure to the worst of it.

Watts Bar Reservoir, Tennessee

Watts Bar Reservoir, on the Tennessee River between Fort Loudoun and Chickamauga, is subject to some of the state's oldest standing fish warnings, and much of the contamination originated at the Oak Ridge nuclear complex and other past industry upstream. PCBs are the main concern, along with mercury, and the reservoir's bed traps polluted sediment that keeps the chemicals in circulation for decades. Tennessee officials tell anglers not to eat striped bass from Watts Bar at all, and it places precautionary limits on catfish and sauger, the bottom-feeding and predatory fish that carry the highest loads. Neighboring reservoirs in the same river system, including Fort Loudoun, Tellico, and Melton Hill, fall under their own PCB and mercury advisories on catfish and largemouth bass. Anglers on any of these waters should check the current state list before keeping a catch.

A Clean-Looking Lake Is Not a Clear One

A fishing advisory is not a reason to give up fish, which remain an excellent source of protein and other nutrients. It is a reason to know the water. The lakes above all hold species flagged as unsafe because of PFAS, mercury, or PCBs, and the advisories are there to help people choose the safer fish and follow the recommended limits rather than give up fishing altogether. The through-line is that a lake can look clean from the shore while the fish living in it carry a chemical history the eye cannot see. As agencies keep testing and tightening their guidance, those warnings remain the most reliable protection for anyone who catches and eats what they pull from these waters.