My Aquarium Has Finished Cycling. What's Next?

Once you have allowed the system to run for a few days after cleaning up the system and doing a water change, test to see if the ammonia and nitrite levels are at zero, and the pH is correct. If any trace of ammonia and/or nitrite is still present, wait until they are gone before you add new livestock, and when all is ready, proceed, but only by adding a few things!

You don't want to overload the system, otherwise a spike in ammonia will likely occur. One or two primary diatom and macroalgae eating fish, such as tangs, angelfishes, and blennies, as well as some snails, hermit crabs and other hardy tank janitors are ideal additions at this point.