Tilapia in outdoor systems

[Marshall Smith]

Out of an abundance of enthusiasm I got a 250gal. IBC tote system set up in the backyard, planted a bunch of plants, and got it cycling with kelp.  Now I realize that I should have thought about fish more first.

This is an outdoor system, no greenhouse, with the growbed on top of the tank in Colorado.  I was thinking about starting with 25 6" tilapia but I'm concerned about the water temperature.  It looks like it's going to be warm enough from here on out but the temperature in the tank swings more than 10 degrees a day.  

Should I be concerned about this?

Should I supplement with a koi pond heater?

Should I do trout instead?

How hardy are these fish?

[George]

I believe they die at 50F, stop feeding at more that - thrive at 80F or so.

[Keith Rowan]

sounds like you're starting with a high stocking density.. how many gallons of growbed/media?  do you have any extra filtration?  any aeration?

 

I started 50 1" tilapia in a single tote system but moved them to the pool after they were 3-4".. if your tote is cut in half (half gb half ft) i'd only stock 15 tilapia to grow out (and i wouldn't grow them much beyone 1lb) in the first year..

 

most of my blue tilapia and nile tilapia survived down to 48f, but were not eating until it warmed up

[Marshall Smith]

It's just one bed which is about 90 gallons with hydroton. It's pretty densely planted.  No extra filtration or aeration though the return feed looks like it provides a lot...

Mostly I'm worried that the temperature swings between 66 and 78 during the day.  I'm going to try to get some insulation but I don't know how much good it will do.  It might also do better when the kelp finishes clearing up.  I just heard that tilapia were sensitive to temperature fluctuations.

[Matt Freshour]

Marshall,

The temperatrue range for Tilapias is 60-95 deg. F, optimal range is 74-80 deg. F. They are very hardy in regards to water temperature, water quality and oxygen levels.

To regulate the temperature and keep it at a more consistent level I would put in a heater in the tank for the cooler CO nights and also cover the tank throughout the day, (we use that blue styrofoam insulation as a makeshift cover).

Trout are a more advanced option for AP systems in that they need consistently cool, fast moving and highly oxygenated water. If you think about the last time you stuck a toe in a mountain stream, thats about what you would need to provide to make them happy.

Additionaly, the water temperatures that trout require (38-68 deg. F, optimal temp range is 55-65 deg. F) are a bit cool for the roots of most warm weather crops to thrive.

Thanks,

Matt

[Marshall Smith]

Awesome, Thanks Matt.

[Nathan Harben]

I insulated around my tank and it made a big difference...just used regular house insulation bats around the sides and covered the top with a tarp. I also have talapia and am super impressed by their hardiness...At first I was experiencing temperature swings of around 10 degrees also between day and night (have the tank in a greenhouse) but the insulation cut that in half...In an ideal system you want minimum temp swing within the range that Matt said...I also have a 300w heater that i switch on during cold nights to reduce the drop but found the best thing to keep the heat is to limit/turn off the water going to the grow beds to reduce heat loss during the night....hope that helps Marshall!