Eager fish keepers will have to restrain themselves for the maturation stage, as it can take several weeks and needs to be done properly to avoid major problems at the start. The aquarium needs to be matured before corals, inverts, or fish can be added, which means it needs to be settled, biologically active, and ready to process waste materials when your first livestock is added.

Adding bacteria
There are many products available for adding bacteria to the aquarium and the process is often called ‘cycling’ or ‘seeding’ as well as ‘maturing’. If you are keeping corals or setting up a reef tank, the best way to do this is with live rock, which is discussed in the next section. For fish-only tanks ask your retailer for their recommended method of cycling, since there are currently several competing methods available and each is hotly debated. The cycling process should take up to four weeks before livestock can be added and during this time you should be testing for ammonia, nitrites, and nitrates. An effective cycle should show a rise in ammonia followed by a rise in nitrite and then nitrate. Once ammonia and nitrites have settled at zero and nitrate is within an acceptable range, you will be ready for your first livestock introduction.