When I first started keeping fish a friend of the family who was into breeding helped me out with the basics and gave me a brief rundown of the dos and don'ts. Among them was a method for cycling a tank without fish and at the same time without dumping ammonia into your tank. After several years I got more involved in fish keeping and adopted the traditional fish cycling method which I have used ever since. Why? I don't know, I guess that was the more common method.

Having to setup a new 90 gallon tank last month, I decided to try the old method once again, this time I am armed with test kits and curiosity so hopefully I'll find out once and for all which method is best, at least for me. It was common sense that this method would work, after all it worked for me for quite some time, but I never tested it or compared it to traditional cycling and assumed that it would not be as efficient.

Tank specs:
Size: 90 Gallon
Substrate: Flourite/Peat
Filter: Eheim 2217
Lighting: 2x40W T12 tubes + 1x15W Tube

This tank is in my wife's office so I really didn't want to make things complicated, nor did I want to go to the office every other day to test the water and make sure the fish used for cycling are OK or need a water change during spikes etc. The old method of cycling that I was shown was to simply add fish food every day, perhaps more than once a day as if I actually had fish in there. The food would fall to the ground, eventually turn into ammonia, and there you have your cycling requirements. The question was just how much longer would this method take? I added a "daily double" automatic feeder and waited it out.

Results
Although I did not perform any scientific or side-by-side testing I do keep logs of my tanks and so I used my logs of the last 3 tanks as a reference guide. All the tanks, including this new 90 gallon were planted with wisteria and other fast growing stem plants to help cycling and to avoid any blooms. I was surprised to find that on average it took one to two days more for the ammonia to spike and about the same for the nitrite spike. In the end the tank cyclied completely in 19 days, that's on average about a day longer than the other tanks took to cycle.

Conclusion
It only takes a day or so for fish food to turn to ammonia on it's own, not much longer than it would for fish to do the same. The tank cycled completely over a week ago and is still holding it's cycle on fish food alone. There was no significant change in the time required to cycle the tank using this method, the extra day or so could have been caused by many other factors such as amount of plants and bacteria brought in by them from my other tanks. I did not have to worry about spikes or water changes to avoid harming any fish, nor did I experience any of the post-cycling blooms I often see with the traditional fishless cycling method of dumping ammonia in the tank.

I'm going back to that 15 year old method! If I'm in a hurry to cycle a tank then I'll seed it from an established tank, otherwise it's "fishless food cycling" for me from here on. OH yeah, and what a nice way to keep a Q-Tank cycled when needed!

Giancarlo Podio
07/08/2003