First Pond Setup: Sand/Gravel Substrate and Goldfish Timing

For a 90-gallon pond with a 600 GPH pump: yes, you can plant directly in 2 inches of play sand topped with gravel. Roots will anchor and draw nutrients. Goldfish can be added now that night temps stay ≥50 °F and day temps reach 62–68 °F.

Feeding Caution

Feed only at midday when water is warmest. Below 50 °F, fish digestion stalls; uneaten food rots, spiking ammonia. Start with a few feeder goldfish (inexpensive, hardy) to test the system.

Filtration Note

A simple intake sponge on the pump is sufficient for this volume and fish load. The pump turnover (~6×/hr) provides good circulation.

Patience and observation are your best tools. Keep asking questions!