Mixing Catfish and Tilapia

[Hollis Armstrong]

I am new to aquaponics but I am very excited about it. I am still in the planning stages of my system so I am exploring all the best ideas because I hope to take this beyond just a back yard hobby. 

I like the idea of tilapia maturing in 8 to 9 months and I like the taste of tilapia. However I dont want to heat the water to 72 degrees all winter in an outside pond so Im thinking of mixing my pond with catfish and tilapia. This should give me a harvest of tilapia just as the cold settles in and the catfish should be about 2/3 grown and should be able to survive the winter if I heat the water a little bit. This will allow me to grow some winter veggies plus allow my catfish to grow to maturity in the required 18 month time frame. 

Im wondering if anyone else is doing this? How is it working out? I have read where the catfish can help the over population problem from the tilapia as they seem to multiply rapidly. This could also help provide supplemental food for the catfish. I would just need to figure out how large I need the catfish to be when I start out the tilapia fingerlings as I think they begin to spawn in 4 to 6 months. If I start out the catfish at the same time as fingerlings will the catfish be large enough to eat the fry from the spawning tilapia? 

I am planning on a pond divided into two sections. One section will be 2600 gallons and the other section will be approximately 3900 gallons for a total of 6500 gallons. I will have a pipe at the bottom with a grate over both ends that will go from one section to the other to help keep the water leveled in both sections. At the top of the divider wall I plan to have a net that will keep the mature fish separated yet allow the fry to pas through.  

I am planning on stocking the pond with 200 tilapia and 300 catfish. I will have 20 4x10 growbeds. I also plan to have a solids filter and to grow snails in it as well as red worms in the grow beds. I think I can process the snails for personal consumption as well as fish food once I get down the process of de-slime them. 

If any of you have done any of this I would appreciate all your feedback positive or negative.