650–750 Gal Pond: 20 Feeder Goldfish, Salt Question

650–750 gal pond, waterfall, ~20 feeder goldfish various sizes. Asks: too many? Salt purpose? Fish/plants healthy without it.

Stocking

OK for ~1 year. At 4" each, need to reduce. 500 gal/adult koi rule; goldfish less but still need space.

Salt Benefits

Goldfish are physiologically "salty" (internal ~0.9% NaCl). External salt (0.1–0.3%) reduces osmotic stress, supports slime coat, inhibits parasites. But: Salt harms plants. Your healthy plants = no salt needed.

Add salt only if fish show stress/parasites. Healthy system = skip it.