New Koi Pond Owners: Fish Deaths, Leaf Fall & Plant Overcrowding

New homeowners inherited a mature koi pond (12+ generations of fish). Recent issues: 3 fish died, a large plant box removed, hot weather, massive tree dropping leaves. Questions: cover pond? Are plants too dense? Need guidance.

Immediate Priorities

1. Aeration 24/7: Hot water holds less oxygen. Run waterfall/fountain continuously.
2. Leaf netting: Install a net NOW—decomposing leaves spike ammonia, drop oxygen, and cause tea-colored water.
3. Plant thinning: Plants should cover 50–70% surface, not "almost fill" the pond. Fish need swimming room and gas exchange area.
4. Filtration check: Ensure biofilter handles current fish load.

Resources for Beginners

Free e-books on pond basics, fish health, and seasonal care are available at www.pondmarket.com (click "e-book" links).

Don't Panic

Mature ponds are resilient. Address oxygen, leaves, and crowding first. Test water (pH, ammonia, nitrite) weekly. Join a local koi club for hands-on mentoring.