Newbie questions, tilapia with catfish? Density? Grow bed?

Shanescaife2

I’m not new to aquaponics on a small scale but am new to the size I’m planning.

I’m building a 18,000 gallon pond with liner. This is a rill style water feature. It will be 4 ft wide, 4 ft deep, and 150 ft long.

My basic questions are; can I raise both tilapia (in summer only) along with Chanel catfish all year? Or will the catfish be to aggressive even in a large system.

Next question, if they can be raised together, how many of each in a system this large? (Next question coves grow area)

This pond will be the center feature of a one acre garden system including both flowers and vegetables. I’m not sure how to figure bed size to fish density. I can have unlimited numbers of beds. So help in figuring how many beds would be greatly appreciated.

The system will be looped, constant flow. From pond to solids collection to 2- 150ft long 1 ft deep constant flow flower beds. Then water will be channeled to a vegetable garden where an assortment of growing options will be used; ie. gutter style wicking system, raft system, pump up to tower type system, and possibly a flood and drain bed.

This will all be outside and open to the public for garden walking tours and sale of fish and vegetables.

I know this is a limited description of the system so please feel free to ask gyration about the design and I’ll do my best to answer.

Thanks for your advice.
Shane Scaife
Hidden Gardens

dstjohn99

I raise both tilapia and channel catfish. I have them in separate systems. However, I have mixed them before with good success. The catfish prefer the bottom while the tilapia spread more. The catfish survive near any temperatures but eat little below 60 degrees. Tilapia eat little below 65 degrees and will die below 55°F (some strains 47°F).

Feeding will be a challenge, as the different size fish will eat at different rates. Have you considered a partition to keep catfish in one area and tilapia in another? Separate progressive sizes for rotation harvest? Separate an area for breeding feeder fish like mosquito fish or fathead minnows?

Tilapia breed readily in most any setting, very rapidly above 80 degrees and pH 8.0. The fry will become food for larger fish. Catfish will not breed until 2 - 3 years old and in the right conditions.
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With primarily DWC beds you will need significant dedicated solids filtration, and bio filtration typically in a 1:1 ratio to fish tank(FT) volume up to 2:1, depending on stocking density.

With an 800 gallon pond I have 800 gallons of wet media for growing / biofiltration and a 65 gallon RFF solids separator. At this ratio I stock up to one pound of fish per 5 gallons of FT water. So with 800 gallons I start with 150 - 160 fish. When they are small the system supports mostly leafy greens, etc. But as the grow and feed rates increase, the system supports a greater variety. If there is a failure point at this density, the system crashes quickly and fish die wholesale.

I am currently converting from hydroton (clay balls) to sand beds. This will eliminate the need for the RFF and provide better aerations, nutrients and flexibility.

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