Aquaponics anyone?

[bobm]

Years ago, I met a guy who grew catfish in those 55 gal. barrels under a lean to on the N side of a small shed to keep the water fairely cool with great success. Used 4 barrels side by side and staggered the start of each by 4 -6 weeks for new fish fry ( he would buy 25 fry at a time from a catfish farm ) so that he had a steady supply of catfish to harvest and eat whenever they were needed. The barrels were covered with 1" x 1" welded wire mesh to prevent the fish from jumping out. Also, there were lights over the barrels to attract flying insects that then would drop down into the water for the fish to eat. He used small aeration pumps to pump in air to the bottom of the barrels to oxygenate the water and fed them commercial fish pellets daily. One could raise Tilapia, Perch, or Sunfish instead if one prefered those insead of catfish.

To complete this thaught.... One could then use a small pump to draw down ( up to about 50% ) and recirculate the fish water into a vegetable growing medium to use the fish waste and uneaten food and disolved nitrogen / nitrates from it to fertilize the plants. Then fill the fish tank with fresh water over and over on a regular basis so the fish have fresh oxygenated water to promote their growth.

 

[Devonviolet]

You're on the right track @bobm. That sounds suspiciously like aquaponics.

If I'm understanding your plan correctly, after the fish water goes through the growing medium, it would be fairly well filtered & oxygenated & voilá - aquaponics! The only need to add water is due to evaporation. No need to add water just to add oxygen to the fish water. The plant roots do that for you. Also, if you let the plant water trickle into the fish tank, the water picks up oxygen from the air it's going through.

I wouldn't think it would be necessary to drain down 50% of the fish water. If you continuously (or even intermittently) circulate the water, with a pump, the water level would remain constant (other than water loss due to evaporation).