Certainly one of the most important considerations for this system is the size. The fish typically maintained in an aggressive tank are usually large animals that consume large amounts of food and are messy eaters. Large Cichlids, Arawanas, and Gars are some examples of commonly available species. Larger than usual filtration is also a factor for this type of system as the volume of water movement and waste export it will need to process is considerable.
Strangly enough, these systems seem to fit well into rooms meant for relaxation. The large predatory fish kept in the Aggressive System are often slow moving laid back fish calmly cruising around waiting for something to eat. The Freshwater Aggressive System is an excellent choice for a powerful showpiece in a quiet setting.
