Colby

Colby is a 518-acre lake located immediately north of Hoyt Lakes. It is comparable to North and South Twin by Aurora, and Bailey's in downtown Virginia. The Partridge River runs through the lake and connects to the upper St. Louis River shortly downstream. This river connection makes Colby's fish community an outlier in the Tower Area. The lake was thermally stratified during the survey and had a surface temperature of 74 °F and a bottom temperature of 53 °F where the depth was 31 feet. Oxygen levels became inadequate for gamefish at 12 feet where the temperature was 63 °F. Secchi visibility was three feet, and the lake had a characteristically dark bog-stain. Aquatic vegetation is sparse in the west basin and relatively abundant in the eastern inlet bay. Shoreline substrates consist largely of boulder and rubble interspersed with areas of sand, muck, and gravel. Development is moderate for the Tower Area, with homes and cabins clustered on the southeast side of the lake adjacent to town along with the Laskin Energy powerplant on the northwest point. The remainder of the lake is largely undeveloped. Total catch in gill nets (10.4/net) was below average compared to past surveys. Black crappie, northern pike, white sucker, and channel catfish represented the bulk of the catch. Walleye, bluegill, golden shiner, shorthead redhorse, yellow bullhead, and yellow perch were present in low abundances. Channel catfish abundance (0.9/gill net, 1.9/trap net) was above average for both gears but lower than in recent surveys. Lengths from combined gears ranged from 14.5 to 28 inches with an average length better than 19 inches. Channel catfish ranged from 4 to 15 years old, but almost all were greater than 10 years old. Colby and adjacent Whitewater provide a locally unique angling opportunity for the species, which is not present outside of the St. Louis River in northeast Minnesota. Northern pike numbers (1.1/gill net) were slightly below average for Colby. Although fewer they were also larger, ranging from 23 to 31 inches with a solid average length of 26 inches the highest recorded out of Colby. The largest pike was sampled in a trap net at nearly 35 inches. Many of the pike sampled were infested with neascus, also known as black spot. It is a fish parasite harmless to humans and removed by cooking fish to temperature. Walleye abundance (0.3/gill net) was below the long-term lake average, but typical for surveys since 2000 when fingerling stocking no longer contributed to the population. Lengths ranged from 11 to 22 inches with an average length approaching 17 inches. Walleyes ages ranged from two to seven years old. Walleye stocking was discontinued due to poor returns of fingerlings and evidence of natural reproduction. Total catch in trap nets (16.1/net) was close to past surveys of Colby. Black crappie and bluegill were most common in the catch followed by northern pike and channel catfish. Low numbers of walleye, shorthead redhorse, hybrid sunfish, rock bass, white sucker, yellow bullhead, and yellow perch were also present. The black crappie catch (4.3/trap net) was identical to the lake average but lower compared to the past two surveys. Sizes were typically small, ranging from 4 to 9.5 inches, with an average length of almost 8 inches which is in-line with past surveys. Gill nets sampled black crappie at a similar rate (4.3/net) with almost identical size structure. Ages ranged from one to nine years, with 2021 and 2019 the most abundant year classes. Growth was very slow for the Area, with mean length at age-4 below 7 inches. Bluegill numbers (5.8/trap net) were average for Colby. Size structure continued a declining trend, with lengths ranging from 3.5 to 7 inches and an average length of less than 6 inches. Bluegill aged from scales ranged from 1 to 7 years with consistent recruitment. Growth was modest for the Area, with age-4 fish averaging 5 inches.

Colby Lake is a 518 acre lake located on the northwest edge of the town of Hoyt Lakes. It is accessed by a concrete ramp on the lake's south shore, with a large parking area available for 20 plus vehicles with trailers. This lake has a maximum depth of 37 feet and dark brown water. Colby was thermally stratified on July 14, 2020 with a surface temperature of 77 F and a bottom temperature of 55 F. Oxygen levels were adequate for gamefish to a depth of 12 feet where the temperature was 68 F. Colby is heavily influenced by the Partridge River which flows in on the east side and out the northwest end. Lake bottom substrates along the shoreline are mostly rubble and gravel with muck in the bays. Several residences line the eastern part of the south shore, but overall Colby is largely undeveloped. The overall gillnet catch rate for all fish combined was 23.0 fish/net which was the highest on record for the lake. The yield was 32.8 lbs/net, which was also the highest on record. Both of these values were heavily influenced by record black crappie and channel catfish catches. Fish species sampled were black crappie, channel catfish, northern pike, yellow perch, white sucker, walleye, shorthead redhorse, largemouth bass, burbot, and bluegill. Trap nets caught fish at an overall rate of 23.4 fish/net which was better than average compared to past surveys on Colby Lake. Yield was 17.3 lbs/net which was also better than the average of all surveys on the lake. Brown bullhead, pumpkinseed, and rock bass were the additional species sampled in trap nets that weren't also sampled in gill nets. The 2020 gill nets sampled 76 channel catfish for a catch rate of 8.4 fish/net. This catch rate was by far the highest on record for Colby. The trapnet catch was also impressive at 4.8 fish/net, also the highest on record for the lake. Lengths ranged from 11 to over 29 inches with an average of 18 inches. This average length was generally slightly smaller than past surveys, however the largest cat sampled was the second biggest on record for Colby. Ages ranged from 5 to 22 years with nearly 87% of the catch 8 years old or older. The northern pike gillnet catch was 2.1 fish/net which was better than the average for Colby Lake, but below average compared to other similar lakes. Lengths ranged from 13 to nearly 30 inches with an average of 22 inches. Nine additional pike were caught in trap nets, the largest individual measured over 35 inches. Four walleye were caught in gill nets for a catch rate of 0.4 fish/net. This catch rate was below average compared to past surveys on Colby. Lengths ranged from 12 to 24 inches with an average of 16.5 inches. The largest walleye captured was 19 years old. Eighty-nine black crappie were sampled in trap nets for a catch rate of 9.9 fish/net which was very good when compared to similar lakes in the state. Eighty-six additional crappie were also sampled in the gill nets for a catch rate of 9.6 fish/net which was by far the highest on record for Colby. Lengths of the combined catch ranged from 5 to 10 inches with an average of 7.5 inches. Sizes were similar to past surveys. Ages ranged from 2 to 14 (N=70) with several strong year classes represented, however growth rates were slow compared to other crappie lakes in the area. Three largemouth bass were sampled and ranged from 12.7 to 16.1 inches long. Bass do not net well so likely they are more abundant than they appear from the low numbers in our survey. The bluegill trapnet catch was 3.7 fish/net which was below average compared to past surveys on Colby. Sizes ranged from 6 to 8 inches.

Colby Lake is located near the city limits of Hoyt Lakes. This popular lake has a public access with two concrete planked boat ramps and ample parking nearby. A playground and swimming beach are also nearby. Most of the development is on the east side. Colby Lake is also used by Minnesota Power for cooling at the Laskin electrical plant on the north side near the outlet. Colby Lake outlets to the Partridge River which joins the St Louis River a few miles downstream. Fish populations in 2015 were sampled with nine trap nets and nine gill nets. Thirteen species of fish were sampled with black crappie and bluegill the only species sampled in above average numbers compared to other similar area lakes. Northern pike and channel catfish were also sampled. Only three walleye were sampled and small yellow perch are present. Colby lake is somewhat unique as it is one of few lakes that have channel catfish in the Tower Fisheries Area. Channel catfish abundance was above average compared to previous assessments on Colby Lake. Catfish average lengths for gill nets and trap nets were 20.8 inches and 18.5 inches, respectively. The largest catfish sampled was 24.3 inches long. Black crappie numbers were higher than the long term average for all assessments on this lake. Crappie were mostly small, averaging 7 inches, although the largest was 10.5 inches long. Bluegill abundance was twice the historic average of 6.6/trap net for all surveys on this lake. The average bluegill sampled was 5.9 inches long and about 6 years old. The largest bluegill sampled was 7.8 inches long. Northern pike abundance was higher than the long term average on this lake. Pike were slightly longer at 22.7 inches compared to past averages. Thirty-six percent of the pike sampled were 24 inches or larger and the largest was 30 inches long.

Based on Minnesota DNR survey data, anglers target Northern Pike, Pumpkinseed, Channel Catfish, Largemouth Bass, and Walleye in Colby. See the full species list above for catch rates, size structure, and quality scores.

Minnesota DNR records list public access for Colby. Check the DNR LakeFinder page for the launch type and directions before you go.

Colby has a maximum depth of 30 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Colby is from 2025.

No invasive species are on record for Colby in Minnesota DNR data. Always clean, drain, and dry your equipment to help keep it that way.