Aquarium Cycling Guide

Cycling is the single most important thing to get right before adding fish — skipping it is the #1 cause of new-tank fish deaths.

What Cycling Actually Does

A new tank has no beneficial bacteria to break down fish waste. Cycling grows a colony of bacteria that converts toxic ammonia into nitrite, then into much less harmful nitrate — the nitrogen cycle.

How Long It Takes

A fishless cycle typically takes 4-6 weeks. It can be sped up with bacteria starter products and a source of ammonia (like fish food or a pure ammonia dose) to feed the developing bacteria.

Signs Your Tank Is Cycled

• Ammonia reads 0 ppm
• Nitrite reads 0 ppm
• Nitrate is present (evidence the cycle completed)
• Readings stay stable for several days in a row

Adding Fish

Add fish gradually once cycled — a handful at a time, not all at once — to let the bacteria colony scale up with the new bio-load.