Aquaponics Starter Kit

The fish excrete ammonia (toxic); nitrifying bacteria (in the grow bed media) convert it to nitrite then nitrate; the plants absorb the nitrate as fertilizer, cleaning the water, which returns to the fish. The bacteria are the engine — the system must "cycle" (establish the bacteria, 4-6 weeks) before it carries fish and plants. The loop is fish-bacteria-plants, all three essential.

Hardy, ammonia-tolerant fish for a beginner — goldfish (cheap, tough) for an ornamental system, or a hardy tropical (guppies, platies) for a display. Tilapia (the food-fish aquaponics standard) need warm water and more space. Start with goldfish (the ornamental loop); graduate to food fish when the system is proven. Match the fish to the system's purpose and temperature.

Leafy greens and herbs — lettuce, basil, spinach (the nitrogen-hungry, fast growers that thrive on fish waste). Fruiting plants (tomatoes, peppers) need more nutrients (and more fish) than a starter system. Start with lettuce and basil (the 30-day crop); the system scales to fruiting as it matures and the fish grow.

Ammonia, nitrite, and nitrate (the loop's health — ammonia and nitrite near zero, nitrate present and falling as plants grow), plus pH (6.8-7.2 for the bacteria and the plants). A water test kit (the drops, not strips) is the dashboard. A new system spikes ammonia then nitrite as it cycles; once nitrate appears and the others fall, the system is cycled and ready for full planting.