Patent ID: 7311822

Claim:
An aquarium for providing water and living space to aquatic animals, the aquarium comprising: a) a container having a height, a length and a depth, the container comprising: (i) a main cavity located inside said container having a first volume; (ii) a lower cavity located inside said container and below said main cavity, said lower cavity having a second volume substantially less than said first volume; and (iii) a first side cavity located inside said container and adjacent to said main cavity, said side cavity having a third volume less than maid first volume and greater than said second volume; and b) a first plate separating said main cavity from said lower cavity, said first plate providing limited fluid communication between said main cavity and said lower cavity in locations extending along at least a substantial part or the length of said container; c) a second plate, said second plate providing a barrier against fluid communication between said main cavity and said side cavity along all but small fraction of the height and depth of said container and said second plate providing limited fluid communication between said main cavity and said side cavity; d) a filtration system in fluid communication with said main cavity for intake of polluted water, said filtration system also in fluid communication with said lower cavity for outgo of purified water after said polluted water has been purified by said filtration system; and e) a second side cavity located inside said container and adjacent to said main cavity, said second side cavity having a fourth volume substantially equal to said third volume.