-The "Fishless Cycle" Using Shrimp
This method is similar to the fish food method but instead of fish food, we supply ammonia using raw shrimp from the seafood section of the grocery store. One medium sized shrimp for every 20 or 30 gallons of water will decay and provide a steady flow of ammonia into the tank. The benefit to using shrimp vs. fish food is that you can put the shrimp into some sort of mesh bag (filter media bags or pantyhose work great) so that the waste can be removed easily at the end of the cycle. Using shrimp also provides a nice steady, even flow of ammonia, something that can be hard to accomplish using only fish food. The steps to the cycle itself are the same as described above. This is likely the easiest method of cycling a tank as all you have to do is add the shrimp, test the water parameters from time to time, remove the shrimp at the end of the cycle and do a water change and you're all set. -The "Fishless Cycle" Using Pure Ammonia
This is the most precise method of cycling your tank. It is similar to the fish food and shrimp methods described above but the ammonia source is pure bottled ammonia. It is of utmost importance that you use only pure ammonia, not ammonia-based cleaning products that contain detergents, dyes, scents or any other chemicals as these can be harmful to your fish. How much ammonia to add depends on the concentration of the ammonia you're using but you want to add enough ammonia to bring the concentration of your tank to 3-5 ppm (this is usually 3-5 drops per ten gallons but can vary). Test the ammonia and nitrite levels every day, adding more ammonia daily as needed to keep the ammonia level at 3-5 ppm. Eventually, you'll notice that the ammonia concentration will start dropping, which goes along with an increase in nitrite. Continue dosing ammonia to the same concentration. Eventually, you'll reach the stage where enough ammonia added to bring the tank to a concentration of 3-5 ppm totally disappears within 24 hours, leaving you with nothing but nitrate. At this point the cycle is complete and you can proceed as above. The difficulty with this method is that testing and ammonia dosing have to be done at least daily. Pure ammonia can also be difficult to track down and the risks, should you use ammonia that contains other chemicals, are serious. Unlike the other methods, however, the pure ammonia method allows you complete control over the cycle and lets you know just how much ammonia your biofilter (i.e. the colonies of beneficial bacteria established during the cycle) can process in a given time period. -The "Planted Tank" Method
This is the only one of the five cycling methods that doesn't involve establishing colonies of beneficial bacteria (or at least that doesn't focus solely on these bacteria as a means to remove harmful chemicals). Like Nitrosomonas bacteria, aquatic plants can use ammonia. However, unlike these bacteria, the plants simply absorb the ammonia and don't produce nitrite as a by-product. For this reason, plants can be thought of as "ammonia sinks" in your aquarium. Aquatic plants also absorb nitrates, but prefer ammonia. The planted tank method, then, is the practice of planting your tank heavily enough that any ammonia your fish might excrete can be absorbed directly by your plants. In other words, you plant the tank very heavily and immediately add a small number of fish, letting the plants take the place of beneficial bacteria as they normally would exist in a cycled tank. Beneficial bacteria will be present and as a result you will eventually get some nitrate readings in the tank (though often at such low concentrations to be of no concern). However, most of the ammonia is taken care of by the plants. This method can be risky as it's difficult to know exactly how much ammonia your plants are capable of absorbing. If the plants aren't receiving proper care in other arenas (lighting and other nutrients) they may not be capable of absorbing the quantities of ammonia that would be needed in order for your tank to be cycled using only plants. Because of the additional considerations of caring for the plants that provide the ammonia removal in this method, the "planted tank cycle" is only recommended to aquarists that have some experience in keeping live aquarium plants and who have some feel for the relationship between plant and fish stocking levels in terms of the plants' ability to utilize the ammonia that fish produce. Which method is best for me?
If you've already got fish in the tank, you're essentially stuck with the "fish-in" cycle as your only option unless you're willing to return the fish and do a fishless cycle. Any of the fishless cycling methods described above will work but I find the shrimp method to be the easiest and least labor-intensive. Once you choose your cycling method and complete your cycle, you're ready to begin adding fish. While some of these methods theoretically allow you to fully stock your tank right away (especially the ammonia dosing method which should allow you to establish relatively huge numbers of beneficial bacteria), in practice it is always safer to stock your tank slowly no matter how the tank was cycled. "Seeding" your tank to "kick start" the cycle:
As mentioned above, beneficial bacteria live almost exclusively on the surfaces in your aquarium, not in the aquarium water itself. Thankfully, this means that it's relatively easy to "kick start" the cycle, no matter which method you're using, by "seeding" your tank with bacteria from an already established tank. There are a number of ways to do this. The simplest is to simply move some of the decor (driftwood, rocks, plants, artificial decor) from the established tank into the cycling tank, bringing bacteria with it. You can put bacteria-rich substrate into a mesh bag and put this in your filter or in a high-flow area on top of the cycling tank's substrate. Perhaps the best seeding method is to literally move some filter media (sponges, ceramic rings, filter floss, etc.) from an established tank's filter into the cycling tank's filter. When moving decor, substrate or filter media from an established tank to the cycling tank, be sure to keep any of these materials wet as any beneficial bacteria they house will die if the material dries out. If it's not possible to physically move the filter media, you can squeeze the media into the cycling tank's filter, which deposits some bacteria on your new filter's media and on the other surfaces in your tank. Because very few bacteria actually live in the water column, moving water from an established tank to a new cycling tank is ineffective as a means of seeding the new tank. There are also "bacteria in a bottle" products designed to add beneficial bacteria directly to your tank, some even claiming that they'll instantly cycle your tank for you. If you choose to use one of these products, make sure that you go for the type that needs to be refrigerated (bacteria are living organisms, after all). Results seem to be mixed with some reporting great success and others saying the product didn't seem to make a difference. While seeding a tank can have observable positive effects on the aquarium cycle it is not a substitute for cycling but rather a means to aid it. For this reason, caution should be taken not to place too much stress on whatever bacteria might have been introduced as it takes time for them to multiply. An extra tidbit:
The following was mentioned to me by Thunderloon via PM:
"I've found that one of the further risks in live cycling of a tank is that the Nitrospira will also eat ammonia until it is gone and won't switch to nitrite until then.
This is symptomatic from people who's cycle started but the nitrite is climbing off the scale with zero produced nitrate.
Also a nitrate over about 400ppm will stop spira and somona from being able to "poop"
This is simple in the fishless cycle but problematic otherwise."
I'm already quite the fishless cycle proponent, but this information is yet more reason to use a fishless method rather than a fish-in cycle, as dealing with the above effects with live fish in the tank would be stressful for both you and the fish. Written and posted by: IamntBatman 3/04/2010