Big Fish Lake vs Cedar Island Lake
Water quality, depth, fish species, and recreation comparison.
Big Fish Lake has a higher water quality grade (A, Excellent) than Cedar Island Lake (F, Very Poor). Both are in Stearns County, Minnesota.
Big Fish Lake and Cedar Island Lake are both in Minnesota — a same-state head-to-head where the comparison comes down to lake-specific differences in depth, watershed, and monitoring history rather than the broader state-level water-quality regime. Big Fish Lake (A) is materially cleaner than Cedar Island Lake (F). A gap that wide is unlikely to close in a single year of remediation work; it reflects multi-decade differences in the lakes themselves.
For a recreational visitor, the wider grade gap is decisive — Big Fish Lake is the better water-quality choice. For a researcher, the gap is the interesting part: what is different about the two watersheds, and which of those differences is mutable?
Big Fish Lake
Crystal clear, you can see 20 ft down.
Cedar Island Lake
Murky, only visible to about 3.5 ft.
Side-by-Side Metrics
| Metric | Big Fish Lake | Cedar Island Lake |
|---|---|---|
| Overall Grade | A (Excellent) | F (Very Poor) |
| Water Clarity | 20 ft | 3.5 ft |
| Phosphorus | 9 µg/L | 63.5 µg/L |
| Chlorophyll-a (Algae) | 1.8 µg/L | 44 µg/L |
| Maximum Depth | 70 ft | 75 ft |
| Surface Area | 557 acres | 986 acres |
| Public Access | Yes | Yes |
| Fish Species | 15 | 22 |
| Trophic State | oligotrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Big Fish Lake wins on overall water quality with a Grade A versus Cedar Island Lake's Grade F. Water clarity: 20 ft vs 3.5 ft. For more fish-species variety, Cedar Island Lake edges ahead with 22 documented species.
Source: EPA National Aquatic Resource Surveys, 2026.