Furnishing the aquarium is straightfoward. If undergravel filtration is to be used then a fairly deep layer of substrate will be needed; this should be divided into two layers separated by a 'Gravel Tidy' to prevent digging fish uncovering the filter plates.

Deep substrate is not required where living rock will be used and just a cosmetic layer over the tank base will suffice. Stand rocks on the tank base to prevent them being toppled by digging fish. Preparation is everything. The 'furnished' aquarium must be allowed to mature before any livestock is added. This important period is often called the 'break-in period' and, depending on certain circumstances, can take up to three months or more. To become mature, the aquarium must develop the necessary bacterial life which will then dispose of toxic substances (see Filtration Systems).

Whereas in the past, skeletal remains of dead corals was the normal decoration, nowadays the emphasis is on living soft and hard corals. However, there is a good number of very realistic replicas available commercially which are very hard to tell apart from the real thing.

The impressive displays in large public aquaria are usually fabricated from fibre-glass or concrete moulded from real life examples: once covered with a layer of algae, they are also indistinguishable from the living original.

Another benefit to be had from adopting this technique is that the living corals need no longer be harvested from the wild, a strong conservational reason if ever one was needed.

Regularly test for Ammonia, Nitrite and Nitrate in the first days and weeks. However, if the aquarium is furnished with the appropriate amount of living rock, then the maturation time may prove to be shorter. There is no need for the protein skimmer to be operating as until livestock are present there will be little organic matter for it to remove; any existing organic matter can be more beneficial at this stage in helping establish the nitrifying bacterial colonies.

Generally, there will be a 'peak' and rapid fall of ammonia first, followed by another 'peak' and rapid fall of nitrite and then nitrate levels will be seen to be gradually rising. Once nitrate 'appears' the bacterial colony has become established.

The problem with this 'break-in period' is that apart from having nothing for the fishkeeper to watch, the bacterial colonies won't get established ulness they are provided with ammunition to work on. Livestock, in the form of one or two 'nitrite-tolerant' fish could be added to provide the necessary waste products although using any of the various 'maturation fluids' or 'biological filter accelerators' available from your aquatic outlet is just as good - and avoids stressing any fish.

Including a 'clean-up gang' of Hermit Crabs and/or Turbo Snails (half a dozen of each will do) right from the start will also ensure than any algae that starts to form will be kept in check.

Even though the bacterial colonies may well be in place, you must not immediately stock the tank to its theoretically full capacity. The filter's efficiency must grow in step with gradual increases in livestock.