What is the difference between a cycled tank and a mature tank? How can this affect a cephalopod? It is my understanding (and I may be wrong) that a tank can cycle rather quickly (about one month with live rock) and have ammonia, nitrate and nitrite levels near zero. I thought that the reason you are supposed to wait three months before introducing a cephalopod was to give the bacteria a chance to populate the live rock, substrate and other surfaces in the tank. Once the population of bacteria is high enough, it can handle (and convert) the waste that a cephalopod produces. Experts, any input here?