Having familiarized yourself with THE NITROGEN CYCLE, it's now time to discuss how this beneficial process can be begun and maintained in a home aquarium.


Cycling a tank involves the fishkeeper creating and maintaining conditions within the tank that will foster the growth of nitrifying bacteria. These bacteria are cultivated to the point that they can process, and thus counterbalance, the total waste (the "bioload") produced by the fish living in the tank


There are two main methods of cultivating nitrifying filter bacteria - the older,"fish-in" cycling method, or the relatively newer "fishless" cycle - both methods are compared below.


At Betta Late Than Never, we do not condone the "fish in" cycling method due to the potential for serious harm and death to fish involved, and because of the existence of a more humane, and generally superior, alternative - the FISHLESS CYCLING METHOD. Please visit our page to learn the method and some tips for completing a fishless cycle of your own!


Relies on the "artificial" input of pure ammonia by the fishkeeper into a new tank with no creatures living in it to feed the colonies of nitrifying bacteria as they develop. Relies on the waste output of hardy "starter fish" to feed the colonies of nitrifying bacteria as they develop.
  • No fish are subjected to the incredibly high/toxic levels of ammonia and nitrate that appear during a cycle.
  • Larger bacterial colonies can be developed
    • Can fully stock tank once cycle completes, as opposed to adding a few fish at a time (as you established a large bacterial colony)
  • No water changes required while cycling
    • Ammonia and nitrite levels can be allowed to spike uncontrolled as there are no creatures in the tank who will be harmed by them.
  • Cycle may complete more quickly 
    • Because ammonia and nitrite may be allowed to spike wildly, there is more available to feed developing bacterial colonies
  • Fish are in the tank immediately
  • No fish are in the tank until the cycle completes
  • Toxic levels of ammonia and nitrite that develop during the cycling process will injure "starter" fish severely, killing some or all of them
    • Those who do not die have still suffered irreversible damage from exposure
  • Frequent water changes may be needed
    • To control deadly ammonia/nitrite spikes
    • This may in turn slow the cycling process down by depleting available "food" for the bacteria
  • Bacterial colonies established are not that large
    • Fish must be added one or two at a time over days/weeks so as not to cause ammonia spikes