Anyone who has looked at a Candlewood Lake listing lately has seen the phrase "clear water, no weeds." It is true, and the reason it is true is written down in a federal filing most buyers will never open. On March 31, 2025, FirstLight Power Services LLC, "as agent for FirstLight CT Housatonic LLC," filed with the Federal Energy Regulatory Commission its "2024 Annual Report of the Nuisance Species Monitoring Plan (NSMP) Technical Advisory Committee" for "Housatonic River Project P-2576-058." The 81 page package carries the November 2024 plant survey by Northeast Aquatic Research, the Candlewood Lake Authority's written objection, FirstLight's reply, the minutes of a March 18, 2025 meeting where the state fisheries biologist explained how many grass carp have been taken out of the lake and what happened at a similar lake in New York, and a draft of a revised monitoring plan. It is posted on the Authority's Reports page as the 2024 Candlewood plant survey. Read as a buyer, it answers two questions a listing never will: why the weeds are gone, and what has to happen for them to come back.
Every figure and quotation below is from that filing, as printed. Where a number comes from meeting minutes rather than the survey, I say who said it.
What the 2024 survey found in Candlewood
Northeast Aquatic Research has run the "Article 409" plant monitoring for FirstLight "in 2024, and each of the last 6 years beginning in 2018." In 2024 it spent 13 days on Lake Lillinonah and 2 on Candlewood, September 6 and 16, because "due to the extremely limited plant growth in Candlewood Lake in 2023, the 2024 survey was shortened to 2 days." Its purpose was narrow: "verifying that Eurasian Milfoil (Myriophyllum spicatum) is still virtually nonexistent, verifying that other known invasive aquatic plant species remain in the lake (Najas minor and Glossostigma cleistanthum), and inspecting the boat ramps that were used during this survey for the presence of Hydrilla (Lattins Cove, Squantz, Sherman, and New Milford ramps)."
The Candlewood result: "The three invasives species that were documented in Candlewood Lake in 2023 were present again in 2024: Mudmat (Glossostigma cleistanthum), Eurasian Milfoil (Myriophyllum spicatum), and Brittle Naiad (Najas minor)." Milfoil, the plant that once filled the coves, is now a handful of stems: "In 2023, Eurasian Milfoil was found at just three waypoints despite thorough surveying of the entire littoral zone. In 2024, this species was found at two of those three locations, along with a third location near the Lattins Cove Boat Launch. In each case, only one or a few plants were found, always in less than 3.5ft of water." Brittle naiad "was found at just one waypoint, in moderate abundance, near the southern end of Danbury Bay." Mudmat, "a tiny plant with ¼ inch leaves that grows as a carpet over and within sandy substrate where water is only a few inches deep," is "very likely un-grazed by the Grass Carp." Five native species were recorded, each "often less than 1 inch in height," found "growing inside loose gravel or sand." No hydrilla was found at any Candlewood ramp.
Squantz Pond, surveyed August 7, carried two invasives: mudmat at five shoreline locations, and brittle naiad "at sparse abundance in one location near the boat ramp. This is the first time this species has been found in the lake since 2019."
Why the weeds are gone: the carp, in the state's own numbers
The draft revised plan gives the stocking history in one sentence: "In 2015, the CLA secured permits from the CT DEEP to emigrate 3,868 grass carp (Ctenopharyngodon idella) into Candlewood Lake, followed by a second stocking of 5,035 fish in 2017, suggesting the lake contained 8,903 grass carp at the end of the year 2017." The result, in the plan's words: "Eurasian milfoil disappeared from Candlewood Lake (and Squantz Pond). As per the Plan, monitoring conducted at Candlewood Lake in 2022, 2023, and 2024, found virtually no Eurasian watermilfoil." And: "No plant beds (only a few isolated shoots tucked under docks or inside of rocks) were found during each of the 2022, 2023, and 2024 surveys."
At the March 18, 2025 meeting, Joe Cassone of the state Department of Energy and Environmental Protection's Fisheries Division gave the removal count: "we've done, out of Candlewood around 460 carp coming out, which ends up being around 6 tons of carp. When we started removals in 2023, we were looking at a population estimate of 1500 to 3800, depending on which mortality rate would be used." He described the most effective removals as spring work "when the water's cold and the fish are somewhat aggregated, like the back of Brookfield Bay, which has a little four acre zone. We got 133 out of that zone in one event," and the goal: "we're hoping to get a couple 100 out this spring so we could be at a point of recovery soon. Whether it's this year or early next, that's possible."
He also gave the comparison a buyer should keep. Lake Mahopac in Westchester County, "smaller than but similar to Candlewood in that there was a milfoil lake with grass Carp. They put carp in in '93. They lost all their plants within three years and there were no removals there and you didn't see client recovery until 2012. You started to see just a little detectable appreciable amount come back and within three years of that first detection they were back to pre-carp levels." The Authority's executive director, Mark Howarth, put the uncertainty plainly: "we don't know when those plants are going to start to return in a meaningful way, and it could be this year with more removals. We don't really know exactly what that tipping point is. Certainly, we didn't realize that they were going to disappear in one year, so they could return quite, quite suddenly too."
The argument over how hard to look
FirstLight's draft plan cuts Candlewood's survey to a single day: "An annual whole lake survey to determine the acreage of Eurasian watermilfoil is no longer warranted." "Monitoring of Candlewood Lake will consist of one day of field time to check specific known hot spots for Eurasian milfoil and hydrilla. Each of the two State of CT boat ramps will be searched for recent introductions of hydrilla. Annual littoral zone monitoring will be reinstated after prolific revegetation is found by the Agencies."
The Authority objected in writing on December 30, 2024: "While Candlewood Lake Authority still has very little plant materials as of this writing, we'd still like to request that the full survey of Candlewood begin again as normal in the 2025 season. As nearby waterbodies are invaded by Hydrilla, we'd like every opportunity to catch it early and engage a rapid response procedure that we are in the process of developing in preparation." FirstLight's response in the filing: "given the relative abundance of triploid grass carp within the impoundment, the monitoring of public boat launches, including state and municipal ramps, and areas with historically dense milfoil populations sufficiently address the CLA's concerns with regards to early detection of hydrilla. If prolific revegetation within the lake is found by CLA, CT DEEP, or NEAR, FirstLight will resume surveying the entire littoral zone."
At the meeting, the Authority's Director of Ecology, Neil Stalter, said: "I don't love the idea of just a one day monitoring in the largest and busiest lake in the state," and gave the reason the boat ramps are not enough: "we found zebra mussels on the tip of Vaughn's Neck, which seems like totally random." The state's biologist added that "Hydrilla has been found in several drinking water reservoirs that don't have boating access." Northeast Aquatic Research's George Knoecklein answered with the carp: "as long as we have carp in there, the carp are going to eat the hydrilla. That's just plain and simple what is going to happen." The compromise on the table by the end was an early look and a September sweep, with the survey firm's timing rule: "we can't find it in May. It's not up yet. What we usually find is small shoots coming up mid-June," so "we don't expect to find hydrilla before June 15th," and "we kind of use September as the real survey for looking for hydrilla because that's getting to about the maximum growth in September."
What hydrilla did next door
The reason the argument matters sits one dam downstream. In Lake Lillinonah, where hydrilla was first documented in 2023, the 2024 survey found it covering about 3 acres, "the largest beds" at "the Bridgewater Town boat ramp," with smaller patches around Goodyear Island and Poison Ivy Island, growing "in water up to 10.5 feet deep." Eurasian milfoil there totaled about 94 acres, brittle naiad "more than tripled in coverage between 2023 and 2024," from about 13 acres to about 43, and curly leaf pondweed went from "a single small patch" to 5 acres. Three fluridone treatments were applied on September 5, September 27 and October 11, 2024; the October 21 inspection found the Bridgewater beds "mostly brown" but with "green shoots still present," and the report's instruction for the next year was that "the herbicide should be administered on July 1st." Water chestnut was hand pulled by volunteers and a contractor who removed "77.5 cubic yards (15,655 gallons) of plant material." On Lake Zoar, with no herbicide treatment since 2022, milfoil roughly doubled from 23 acres in 2022 to 49.8 in 2024, still below the 114 acres of 2018.
Candlewood's stewards counted three inspected boats arriving from Lillinonah in 2025, which is the traffic the whole filing is worried about; who launches on Candlewood Lake has that count, and the Lake Lillinonah overview and Lake Zoar for a second home carry the two lakes where the plants still grow.
What this means for a lakefront buyer
- "No weeds" is a management outcome, not a lake trait. The plants left because 8,903 sterile carp were stocked in 2015 and 2017. The state has been removing them since 2023 on purpose, and its own comparison lake went from nothing back to pre-carp levels within three years of the first regrowth. Buy the water you see, but price in the water the filing describes.
- The first plants come back at the dock. Every milfoil stem found in 2024 was in less than 3.5 feet of water, "tucked under docks or inside of rocks." The strip in front of a lakefront lot is where the return will show first, and where a hydrilla fragment off a visiting boat would land.
- The survey that would catch it early has been cut to a day. FirstLight's plan checks the two state ramps and known hot spots; the Authority asked for the full survey and did not get it. A buyer's own eyes on the shallows in June and September are part of the monitoring now.
- Read the drawdown in this light. The same meeting recorded that the winter drawdowns "are now effectively managing zebra mussels reoccupation" rather than weeds, which is why Candlewood Lake's 2026 deep drawdown and the 2026 refill read differently than they did a decade ago.
- Pair it with the chemistry. The Authority's 2025 water quality report flags "the continued lack of macrophyte plants" as one of the ecosystem's concerning changes; Candlewood Lake water quality in 2025 has that side, and zebra mussels are in Candlewood, hydrilla is not yet has the mussels.
What the Authority's own 2023 strategy adds
The Candlewood Lake Authority published its own account of the change a year and a half before the FERC filing, an eight page document dated July 27, 2023 and titled "Candlewood Lake Plant Management Strategy 2023: 'Striking the Balance.'" It sets the scale the survey numbers sit against. Milfoil "likely infested Candlewood Lake by hitching a ride from another lake on a boat in the 1970's" and grew to "80% of all lake plants in Candlewood"; the plant community "has been regularly monitored every year since 2007, and since then there has consistently been 300-500 acres of milfoil in the lake." The stocking rate was "15 fish per acre of milfoil in the lake," set by the state, and the strategy prints the stockings as "one of 3,813 fish in 2015, and a follow up stocking of 4450 fish in 2017. 585 fish were also stocked in Squantz Pond in 2017." Those figures differ from the 3,868 and 5,035 printed in FirstLight's 2025 draft plan quoted above; both documents are reproduced here as printed, and a buyer should treat the exact count as uncertain and the order of magnitude as not.
The strategy also dates the collapse and names the goal. "It was recognized in June of 2022 that the lake's normally abundant plant life has been almost entirely absent," after Squantz Pond "lost most of its plant material in 2019." The target the Authority, the state and FirstLight agreed on is not a return to the old lake: "the goal is balancing the ecosystem between overabundance and shortage of plants. This would probably look something like 60-150 total acres of reasonably dense plant material that ideally does not grow to the surface very often." The method, as written in 2023, is the one the 2025 minutes describe in progress: "In the immediate future, that means a shallower drawdown in the wintertime, and small removals of parts of the grass carp population until we begin to see the plants returning." Two of its answers to owners' questions bear on a purchase: the carp have not died off because "when there's no other option, they eat the decomposing algae and biological material at the bottom of the lake," and they are not breeding, since "juvenile grass carp have never been found in the lake by the CLA, homeowners, anglers, or by DEEP during the initial removals."
What the state says on its own page
The Department of Energy and Environmental Protection keeps a page titled "Removing Triploid Grass Carp from Candlewood Lake and Squantz Pond," with content last updated in April 2025, and it states the policy in plainer terms than the filing. "During 2022, the coverage of all submerged aquatic vegetation in Candlewood Lake dramatically declined to the point that it was largely absent from the lake." "Relying on natural mortality alone, it could take upwards of 20 years for the carp population to decline to levels that allow for the recovery of the aquatic plant community," which the Fisheries Division calls "unacceptable." The count: "In May 2023, CT DEEP Fisheries staff conducted a pilot Triploid Grass Carp removal program over the course of 3 days, using a combination of boat-based electrofishing and large mesh gill nets. During the 3-day pilot program, a total of 118 grass carp were removed from Candlewood Lake," and "the Fisheries Division has since removed a total of 460 Triploid Grass Carp." The forecast: removals "will continue until vegetation recovery is observed," and "there is potential that vegetation recovery could be achieved with the removal of an additional 100-600 carp," after which "there is evidence that vegetation could fully recover within 3 years." The state has also opened the removal to the public: anglers can "register as a volunteer angler, report your catch, or view the submitted catches to-date on our public dashboard," under a scientific collector's permit, with a note that "Bow and Arrow fishing, while currently legal for Common Carp, is not currently an allowed method for Triploid Grass Carp." For a buyer the useful line is the range: somewhere between 100 and 600 more carp out, and the state expects the plants back within about three years of the turn.
Update, September 2026: the state finally printed a removal number
The filing above sets out the stocking, and the Authority's own minutes say the removals continue. What neither gives is a running total. Connecticut's 2026 Fishing Guide does. In a page addressed to anglers, the Department of Energy and Environmental Protection restates the history in its own words, that "The sterile Grass Carp were stocked in 2015 and 2017 to reduce the spread of this invasive plant, however by 2022, coverage of all submerged aquatic vegetation in Candlewood Lake dramatically declined to the point that it was largely absent from the lake," and then gives the figure: "DEEP has begun actively removing the carp to speed up lake recovery, having already removed over six hundred fish since 2023." Six hundred is the state's own count, printed in a 2026 publication, and it is the first number anyone has published for the removal side of this program rather than the stocking side. Read it against the thousands stocked and the scale of the job is clear. The Authority's August 12, 2026 minutes add that "DEEP will do more carp removal in the fall," so the total is still moving.
Common questions about Candlewood Lake weeds
Why does Candlewood Lake have no weeds?
FirstLight's 2025 filing says the Authority stocked 3,868 grass carp in 2015 and 5,035 in 2017, and that surveys in 2022, 2023 and 2024 "found virtually no Eurasian watermilfoil," with "only a few isolated shoots tucked under docks or inside of rocks."
Will the weeds come back on Candlewood?
The state has removed about 460 carp since 2023 from an estimated population of 1,500 to 3,800 and, in the state biologist's words at the March 2025 meeting, hopes to reach "a point of recovery soon." The Authority's director said plants "could return quite, quite suddenly." No date is given.
Is there hydrilla in Candlewood Lake?
Not as of the 2024 survey, which inspected the Lattins Cove, Squantz, Sherman and New Milford ramps and found none. Hydrilla covered about 3 acres of Lake Lillinonah in 2024.
How often is Candlewood surveyed for invasive plants?
Under FirstLight's draft 2025 plan, "one day of field time" at known hot spots and the two state ramps, with full littoral zone monitoring "reinstated after prolific revegetation is found." The Authority requested a return to the full survey and FirstLight declined pending regrowth.
What invasive plants are in Candlewood now?
Three, per the 2024 survey: mudmat, a few stems of Eurasian milfoil at three shallow locations, and brittle naiad at one waypoint near the southern end of Danbury Bay.
Sources: FirstLight Power Services LLC, as agent for FirstLight CT Housatonic LLC, filing to the Federal Energy Regulatory Commission dated March 31, 2025, Housatonic River Project P-2576-058, "2024 Annual Report of the Nuisance Species Monitoring Plan (NSMP) Technical Advisory Committee and the 2025 Rocky River Drawdown (RRD) Technical Advisory Committee Meeting Materials," 81 pages, posted on the Candlewood Lake Authority's Reports page as the 2024 Candlewood Plant Survey and downloaded September 4, 2026: Attachment A, Northeast Aquatic Research, "2024 Monitoring Report, Article 409 Nuisance Plant Monitoring of Lakes; Candlewood, Lillinonah, Squantz, and Zoar," November 2024 (executive summary, survey methods, Lake Lillinonah results and Table 2, post treatment hydrilla inspection, Lake Zoar results and Tables 4 and 5, Candlewood Lake results, Squantz Pond results and Table 7); the consultation record with the Candlewood Lake Authority's December 30, 2024 comment and FirstLight's response; Attachment B, the March 18, 2025 Nuisance Aquatic Species Monitoring Plan meeting agenda and minutes; Attachment C, the draft revised Nuisance Aquatic Species Monitoring Plan; Attachment D, the March 18, 2025 Rocky River Technical Drawdown meeting minutes. Speakers are identified as the minutes identify them.
Related reading:Candlewood's drawdown, in FirstLight's own words, what the Candlewood Lake Authority asks of a lakefront owner, Squantz Pond, the natural lake attached to Candlewood and the Candlewood Lake overview.
If you want a lakefront lot read against the plant survey, the carp count and the hydrilla watch before you write, reach me through ConnorCTHomes.com.
Connor Kostyra, Licensed Real Estate Salesperson, CT Lic. RES.0836348.
Connor CT Homes is a marketing brand. Real estate services are provided through RE/MAX Rise, 1297 Main Street, Watertown, CT 06795.
This article is general information, not legal or environmental advice. Figures and statements are quoted from FirstLight's March 31, 2025 FERC filing and its attachments as printed; meeting remarks are attributed as the minutes attribute them and describe conditions in 2024 and early 2025. Plant conditions, carp numbers and monitoring plans change. Confirm current conditions with the Candlewood Lake Authority and the state before relying on anything here.
