Fish Lake
Fish Lake in Chisago County, Minnesota has a water quality grade of A (Excellent). Water clarity: 9.4 ft visibility. Phosphorus: 14.5 µg/L. Chlorophyll-a (algae): 3 µg/L. Maximum depth: 57 ft. Surface area: 318.82 acres.
- Clarity
- 9.4 ft
- Typical in August
- 74°F
- Max depth
- 57 ft
- Area
- 319 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 13
Next lake in Chisago County
Fish Lake is a 319-acre mesotrophic lake in Chisago County, Minnesota with a maximum depth of 57 feet (16-foot average). Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 13 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 29 other monitored lakes in Chisago County, Fish Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-22. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Moderate clarity, visible to about 9.4 ft. Phosphorus level: 14.5 µg/L. Chlorophyll-a: 3 µg/L. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 9.4 ft | Not graded |
| Phosphorus | 14.5 µg/L | Good |
| Chlorophyll-a (Algae) | 3 µg/L | Good |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Fish Lake
Compare lakeside cabins, hotels, and vacation rentals near Fish Lake in Chisago County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
Top-rated places to stay near Fish Lake
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Water Temperature
Fish Lake typically sits around 74°F at the surface in August. Summer average is about 75°F. Usually warmest in Jul (about 79°F) and coldest in May (about 63°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 45 field readings (2017–2025) via the EPA Water Quality Portal. See the full Fish Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Fish Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (97,275 cells/mL) on November 13, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 57 ft |
| Average Depth | 16 ft |
| Surface Area | 319 acres |
| Shoreline Length | 3.3 mi |
| Littoral Zone | 44% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Fish LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Fish Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
DNR Fisheries Survey Summary
8 surveys on file from MN DNR Fisheries. Most recent: 2020-07-27 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| SUN | 88.92 | — |
| Bluegill | 30.08 | 0.17 lb |
| Bluntnose Minnow | 27.09 | — |
| BKS | 18.59 | — |
| Largemouth Bass | 18.29 | 0.86 lb |
| BKF | 10.45 | — |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Bluegill
BKS
Largemouth Bass
From the 2020-07-27 survey
A targeted survey of the nearshore fish community in Fish Lake was conducted by Fisheries Index of Biological Integrity (IBI) Program Staff starting on July 27, 2020. Ten sampling sites were evenly spaced around the lake and each was sampled by backpack electrofishing and seining with a 15-foot or 50-foot seine, where…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Fish Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — FishFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — FishFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — FishPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | -0.023 m/yr | 6 |
| Phosphorus | ↑ Improving | -1.22 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.74 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (54 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2012-03-20 (2012) | 2013-05-06 (2013) |
| Ice-In | 2010-12-02 (2010) | 2009-12-06 (2009) |
Most recent ice-out: 2026-04-02
EPA Impairment Status
Fish Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN13-0068-00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Fish Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Harris WwtpHarris · 2.8 mi away · NPDES MN0050130Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #1 of 30 lakes in Chisago County
Nearby Lakes in Chisago County
Frequently asked questions about Fish Lake
What is the water quality grade for Fish Lake?
- Fish Lake in Chisago County, Minnesota has a water quality grade of A (Excellent). Water clarity: 9.4 ft visibility. Phosphorus: 14.5 µg/L. Chlorophyll-a (algae): 3 µg/L. Maximum depth: 57 ft. Surface area: 318.82 acres.
Is Fish Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Fish Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 3 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Fish Lake?
- Fish Lake typically sits around 74°F at the surface in August, from 45 EPA Water Quality Portal field readings (2017–2025). That is a typical value for the month, not a live reading.
How deep is Fish Lake?
- Fish Lake has a maximum depth of 57 feet and an average depth of 16 feet. The lake covers 318.82 acres.
What fish are in Fish Lake?
- Fish species found in Fish Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, yellow bullhead, yellow perch. Fish Lake is located in Chisago County, Minnesota.
When does Fish Lake thaw?
- Fish Lake typically has ice-out around Apr 13.
Does Fish Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Fish Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (97,275 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Fish Lake?
- Fish Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Fish Lake. Public access is listed as yes.
Explore Fish Lake across LakeGrade
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Moderate nutrients, good water quality
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Where this data comes from
96 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA96 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- Phosphorus by Colorimetry
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (2)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate