World Conservation Monitoring Centre provides objective, scientifically rigorous and focused information on global biodiversity and the sustainable use of the world's living resources.

Since 1993, UNEP-WCMC has been developing the most detailed global map of coral reefs. This information represents a critical part of the increasing information base now available describing coral reefs world-wide.

One type of marine aquarium never fails to create a stir, the fish-only tank containing BIG fish! The sight of large slices of brightly coloured piscine flesh cruising around an equally spacious aquarium is enough to make anyone's heart beat a little quicker. Such displays are normally the province of the public aquarium, but within the confines of a domestic setting the whole thing can be replicated on a somewhat smaller scale with equally stunning results.

The Tank

There has to be a lower size limit to an aquarium housing big fish otherwise overstocking is quickly going to become a major problem. In addition, keeping large fish in a small aquarium is cruel and stressful, leading to disease, stunted growth and in all probability, a premature death. Of course, juvenile specimens can be housed in smaller accommodation, but the fishkeeper will soon have to make plans for a larger tank.

After all these years, it turns out that the nitrifying bacteria are not what we thought.

Biological filtration is the critical filtration component in every aquarium. Whether the biological filter is live rock, trickle media, a sponge or any other substrate, the oxidation of ammonia to nitrite and then to nitrate is necessary to keep these substances from reaching toxic concentrations in our aquariums. It has been a basic tenent in biology and the aquarium hobby that there are two bacteria responsible for nitrification. The first, called Nitrosomonas europaea, oxidizes ammonia to nitrite, while the second, Nitrobacter winogradskyi, oxidizes nitrite to nitrate.