Backyard Pond Algae Control: The Fish Stocking Connection

Green algae in your 500-gallon pond with 25 goldfish? You're likely overstocked. Fish waste fuels algae—here's the math.

Stocking Guidelines

• Unfiltered pond: 25 total fish inches max
• Pump/filter: 50 total fish inches
• Premium filter: 100 total fish inches

Your Situation

25 goldfish × ~3-4 inches each = 75-100 fish inches. Even with a filter, you're at or over capacity. Excess nutrients → algae bloom.

Solutions

1. Reduce fish population (rehome some).
2. Upgrade filtration system.
3. Add aquatic plants to compete for nutrients.
4. Install UV clarifier.

Key Principle

Balance fish load with filtration. Algae is a symptom—fix the cause (excess nutrients from overstocking).