Aquarium with closed water recirculatory system for culturing fish and

Abstract

Toxic metabolic products (e.g., ammonia) in water can be decomposed effectively by a close contact of ammonia with oxygen on the large surface area of plastic substrates in the biofilter tank according to the aquarium of the invention. In the conventional method, toxic metabolic products such as ammonia have been oxidized by blowing air into the water or zeolite and activated carbons have been used to absorb unwanted products but which absorbents are required to be replaced or cleaned frequently to remove clogged materials. In contrast, the plastic substrates in the aquarium of the invention does not require such frequent replacement or cleaning. The rearing tank is connected with the biofilter tank and the algae culture tank via the sump, which functions as a buffer to prevent any adversary effect on the aquatic environmental factors in the reading tank. The sump contains a large volume of water, which also serves to minimize a sudden change in culture conditions. These designs of the aquarium of the invention will also serve to minimize losses of cultured aquatic life forms on such occasion.