Fish farm and hydroponic greenhouse

An indoor fish farm, comprising:

• an enclosure;
• a fish tank assembly disposed within the enclosure, the assembly comprising:
• a fish tank adapted for containing water and fish therein;
• one or more air lines positioned at the bottom of the fish tank wherein the one or more air lines are adapted for receiving air and for releasing the air in a column of rising bubbles;
• and
• a biofilter characterized by a surface adapted for supporting microorganisms capable of converting ammonia to nitrite and nitrite to nitrate, wherein the surface is at least partly defined by a plurality of vertical channels, and wherein the biofilter is positioned in the fish tank so that when the tank is filled with water the biofilter will be submerged and the vertical channels will be above the one or more air lines;
• and
• means for maintaining nitrate concentration in the fish water at or below selected levels.

A combined hydroponic greenhouse and fish farm comprising:

• an enclosed fish tank adapted for containing a body of water and fish therein;
• an enclosed hydroponic network in fluid communication with the fish tank;
• and
• means for circulating water from the fish tank, through the hydroponic network and back to the fish tank;
• one or more air lines positioned at the bottom of the fish tank wherein the one or more air lines are adapted for receiving air and for releasing the air in a column of rising bubbles;
• and
• a biofilter characterized by a surface adapted for supporting microorganisms capable of converting ammonia to nitrite and nitrite to nitrate, wherein the surface is at least partly defined by a plurality of vertical channels, and wherein the biofilter is positioned in the fish tank so that when the tank is filled with water the biofilter will be submerged and the vertical channels will be above the one or more air lines;
• and
• means for continuously circulating the water in the fish tank through the biofilter.

A method for growing fish comprising:

• maintaining the growing fish in an enclosed fish tank;
• circulating water from the fish tank through a hydroponic network and back to the fish tank;
• and
• introducing air into one or more air lines at the bottom of the fish tank under a biofilter having a surface defined in part by vertical channels, so that the air is released in columns of bubbles which rise through the vertical channels of the biofilter, whereby water in the fish tank is circulated through the biofilter.

A method for growing plants in a hydroponic network, comprising:

• circulating a substantially constant body of water between the hydroponic network and a fish tank assembly in fluid communication with the hydroponic network, wherein the fish tank assembly comprises:
• an enclosed fish tank adapted for containing a portion of the body of water and fish therein;
• one or more air lines positioned at the bottom of the fish tank, wherein the one or more air lines are adapted for receiving air and for releasing air;
• and
• a biofilter supported in the fish tank over the one or more air lines, the biofilter having a surface supporting microorganisms capable of converting ammonia to nitrite and nitrite to nitrate, wherein the surface is at least partly defined by vertical channels;
• and
• introducing air into the one or more air lines whereby air is released from the one or more air lines in columns of bubbles rising through the vertical channels of the biofilter, thereby aerating the water in the fish tank and creating a current whereby water in the fish tank is circulated therein.