Big Fish Lake

On the LakeGrade rubric, Big Fish Lake pulls an A: clarity at 20.7 ft and 9 µg/L of phosphorus put it in the top bracket for Minnesota. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

Trophically, Big Fish Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. At 70 ft of maximum depth, Big Fish Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. The lake's 557 acres and 5.9 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within Stearns County's 55 graded waters, Big Fish Lake sits at rank 4, near the top of the local distribution.

Zebra mussel presence at Big Fish Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. The fishery includes walleye alongside the lake's other 15 documented species — a notable draw for Minnesota anglers. A documented public access point at Big Fish Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. Ice-out has been recorded 21 times at Big Fish Lake, with a median around Apr 13. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.