I have a freshwater fluval edge which is either 6 or 8 gallon, and it cycled pretty quickly and easily took around 5 days without fish, then I added a couple fish and added a couple more and its been going strong since just done a couple partial water changes. I may be working on a snail infestation though because everyday it seems like I have a couple more in the tank, but I also saw one of my ghost shrimp trying to eat a snail out of its shell, so maybe they will keep the snail population in check, lol