Originally posted by Demosthenes
Seriously though, I say a tank is established after about 18 mos. Most will say earlier, but IMO it's at least a year and a half.
Thank goodness you said this! I agree, BTW, that a tank is still quite unstable at least until it is 12 months old, minimum. This is why, IMO, it should take at least that long before the tank is close to fully stocked. Ideally, it shouldn't be close to fully stocked at that time, but what concerns me is when loads of delicate things- various corals, clams and the like- are added to tanks under 6 months old. What this often leads to is the ever common complete tank crash before the system is 6 months old.