The key part of fishLESS cycle is that there are no fish in the tank. This avoids any problems with fish suffering from ammonia poisoning/burns. This way, by the time fish are added, the biofilter is already there.nitrofish1;2113225; said:you shouldnt need to add ammonia to the water if you use fish to cycle the tank. id add the school of danios and use a bacterial supplement, its not ammonia, but its helps the growth of bacteria in the tank. the danios can take the amount of ammonia that they produce, so you shouldnt need to add any ammonia to the tank, just let the cycle take its course.