Backyard Aquaponics
A place to discuss aquaponics

Hi everyone, I have a humble backyard system running since October of last year. The plants are doing well, and temperatures have started to drop especially at night. I reckon the temperature of FT water to be in between 60 - 68F. My tilapia are not eating but stay at the bottom of the tank.

NO3 0ppm, NO2 0ppm, NH3NH4 0ppm
pH 6.4

I wonder if I should give my tilapia away and power my system with koi since they dont seem to be bothered by temperature fluctuations. I am concerned that nitrates will be lacking if my fish are no longer eating. At advice would be greatly appreciated.

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Hi mate. Although I have no tilapia experience over here we use perch which prefers warmer conditions and during winter they go off the feed. They survive the cooler temps then, when the water warms coming into spring, they’re off again. During winter I have used blood and bone sprinkled on the beds, seaweed solution and fish emulsion to power the system. As long as the growbeds can process the load it’s no problem. Now there is enough solids built up in the beds to keep the plants growing through winter.
The question is can your tilapia survive the temperatures they’ll be subjected to in your area.

Thanks for your input mate! I'm still trying to figure things out. Water parameters seem good with 0.25 ammonia, 0 Nitrites and pH at 6.4

They came up to nibble on my hand last night and they fed normally on sinking pellets but dont seem to rise to the surface to eat the floating pellets like in the warmer seasons. Still scratching my head...

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You have 2 threads of this.

Tilapia are tropical fish 24C/75F minimum.They can survive in lower temperatures.
Koi is a good idea,they will eat when temps are low.

Oh my mistake. It was lagging and I must've submitted twice thinking it didn't go through.

What would you suggest since I want to breed tilapia from protein. But their appetite has considerably reduced now that the temps have dropped. They come and nibble on my hand, eat a few floating pellets and then go back down to the tank. Is there a way to use both koi since they're not fussy, and tilapia also?

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Put a heater in the tank & set it to come on at 21C/69F.
Koi can grow big!,they will also stop eating when the water gets really cold.But Tilapia would die long before that.


What do you mean "from protein"?

I would like to eat the tilapia eventually so I'm not very keen on koi

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I think I’ve seen breeding tilapia done indoors in a controlled environment then grown out in the AP set up. Scotty suggested trout in the other thread but not sure of your water temperature difference summer to winter.

Is there a way for me to delete the second post with the same title?

skeggley: I've checked water parameters and they shouldn't be affecting my tilapia. I dont know why they stay at the bottom of the tank with minimal appetite/not really eating anything. I have to scoop up the uneaten fish food eventually. They were feeding well last week and I haven't done anything to scare them either. Some of the fishes even come up to nibble on my hand when I remove the tank cover. The outside temp has been averaging around 20C during the day, 16C at night.

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You want to eat them.Got it.

Ask a moderator to remove it.

But what's the water temperature?.Even if the water is 20C,that's too cold for any tropical fish.

I'll get it cleared away. I'm the only one who commented on that thread anyway

I'm raising tilapia in USA, southern California. They will stop eating when it is too cold. I've also read that if they do eat when it is too cold, their digestive system will not function as well and it can cause illness or death. Cold water will also damage the tilapia nervous system which I believe is why they die when the water is too cold.

These are tidbits I've collected and opinions vary considerably, so take it for what it's worth.

I do know from experience that when I had Mozambique tilapia (orechromis mozambique) I would keep the water above 70°F, and now that I have Nile tilapia (orechromis niloticus) I can drop it to 65 degrees. But below 70 they eat much less, like only a couple of times a week. Over 75 degrees and I feed two or three times a day.

BTW, to heat my water I have an IBC system and the IBC fishtank is wrapped with rockwool insulation and then plastic. I use a 1500 watt stainless bucket heater available on Amazon for about $40. I use an Inkbird temp controlled. I prefer the wifi model also about $40.

I have melted the plug off the Inkbird because I thought it was only a 1000 watt heater. But after I replaced the plug it has worked quite well.

Thank you for sharing your experience with tilapias. There is some sun during the day and I am thinking that it might help to wrap the tank with a black fabric or membrane in the winter time. Perhaps it may absorb the daytime heat and radiate it to the water which may help to some extent.

Im still trying to wrap my head around it, but the tilapias are coming up to the surface and feeding on sinking pellets. Once the temperature dropped they stopped feeding on their regular feed of floating pellets (?) I cant figure out why because they loved it in warmer temperatures: rising quickly to the surface and splashing the water to feed. At least they are eating the sinking pellets, but they are inferior in quality ingredients. Not sure what's going on and I dont really want to invest in heating up the water as our electricity cost is high.

If any one has experienced this or a theory behind this behaviours, dont be shy to share please.

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This is normal behavior for catfish and bluegill and I suspect for Tilapia. Fish don't feed as much when the waters cold and my bluegill don't come to the surface unless the waters warm (the catfish I had before were the same way).