How to Cycle a Fish Tank: The Complete Guide
By Melbourne Tropical Team Β· 1 min read
A step-by-step guide to the nitrogen cycle and how to cycle a new aquarium safely before adding fish.
What is the nitrogen cycle?
The nitrogen cycle is the biological process where beneficial bacteria convert toxic ammonia into nitrite, then into far less harmful nitrate. Establishing this bacteria colony β 'cycling' β is the single most important step in fishkeeping.
Fishless cycling step by step
Set up your tank and filter, then add a source of ammonia (bottled ammonia or fish food) to reach 2-4 ppm. Test daily. Ammonia will fall as nitrite rises, then nitrite falls as nitrate appears. When both ammonia and nitrite return to zero within 24 hours of dosing, your tank is cycled.
Speeding it up
Seeding your filter with mature media from an established tank, or a quality bottled bacteria starter, can cut cycling from six weeks to one or two. Track your progress with our cycling tracker.