Cold Weather Aquaponics Questions

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As winter continues to creep closer, Dr. Nate Storey of Bright Agrotech is answering a few of your questions about cold weather aquaponics. More specifically, he’ll take questions on: 

  • Fish response to colder temperatures
  • Appropriate temperature ranges for tilapia 
  • Best type of heaters for IBC aquaponic systems



“My fish seem to not be eating as much these days. As the temps drop in my fish tank, will the colder water change the fish’s eating habits?”


Dr. Storey:

It is quite common for fish to slow down when the water gets cold and that leads to lower production as well. As a result of your fish slowing down, there will be fewer nitrates in your solution so you don’t want to overfeed. Its one of those things you’ll need to keep an eye on and make sure you’re feeding appropriately.

If you don’t already, I would recommend figuring out some way to heat your tanks. This way when the weather cools down you won’t decrease your production.


What kind of temperature ranges are most appropriate for tilapia?


Tilapia are definitely warm water fish.

There is a reason they are the most common fish in aquaponics. For starters, they’re very tolerant of poor water quality and they eat almost anything you can feed them. Some folks use traditional fish food, while others choose to supplement this type of feed with duckweed. Heck, you could probably feed them grass clippings if you want. But, while they’ll eat just about anything, the issue with tilapia is that they’re very temperature sensitive. Remember, these fish are primarily coming from Africa or other historically tropical environments.

best fish for aquaponicsFor most tilapia, when the water temperature drops down to about 55 degrees, they will go into a stress induced dormant state. You’ll know this is happening because one day you’ll walk in and those tilapia will be bumping into the walls and swimming around like they’re drunk.

As you can imagine, this isn’t a great state for your fish. It’s actually really dangerous for their biology. Once your water temperature drops down to 50°F you’ve probably killed them.

There are very few tilapia varieties that can withstand those types of temperatures.

I have played  around with various hybrid species before as well. There’s actually a hybrid called a Rocky Mountain White that’s tolerant of cooler temperatures; supposedly this is a fish that can get down around 50°F without croaking.

I’ve also played with some tilapia varieties that aren’t supposed to be cold tolerant at all, like the Nile-based Florida Reds. I say Nile-based because there’s almost no truly pure stock. What I’ve found is that often times the hybrids that are bred for cold tolerance are just poor feeders and gain weight slower than most. I prefer fish that will feed voraciously up until the time that they die over fish that are tolerant of lower water quality.

I will say that exposing your fish to more extreme variables over time, they will adapt. We’ve got a number of generations in our system at Bright Agrotech and I’d be willing to bet that they could occasionally tolerant water temperatures down in the high 40′s.We’ve got this crazy mutt tilapia breed now that seems to tolerate the almost all the abuse we throw at them.

However, if you’re just starting off with tilapia that you order through the mail or get from a friend, you need to keep those water temperatures above 60°F minimum. And, if you want good production, you’re need to keep your temperatures between 70°F and 85°F.


“So the optimal temperature for tilapia is 70 to 85 degrees Fahrenheit. Is that correct?”


Dr. Storey:

That’s where you’re going to get maximum production.



“What is the best type of heater for an IBC system during the cold months?”


There is a wide array of heaters out there for standard IBC aquaponic systems. However, perhaps the best design I’ve seen was on the Aquaponic Gardening site.

This simple and effective design featured only a thermostat and stainless steel water heater element. I think it would be a really great kind of emergency heating technique.

There are many DIY designs out there and of course, there are some commercial products as well. I don’t necessarily have an opinion on some of the commercial designs simply because I’ve never used them, although I’ve heard some negative reviews about  some of them that make me question whether they’re really worth the money.

Definitely go on the Aquaponic Gardening site and search ‘homemade heater’.

There will be some results that come up for stainless steel water heater element base heater and I think it’s a really great way to heat.

Wood Burning Boiler Heating

bright agrotechIf you’ve checked out our furnace video, you’d see that we heat our fish tanks with a series of heated coils coming from our wood furnace.

Now, every system is different and you have to heat your system with the resources specific to and appropriate for your area.

Commercial growers, although backyard hobbyist as well, need know what’s the cheapest fuel and the easiest way to deliver heat to their system.

This sometimes requires a little creativity by the grower to devise an appropriate way to heating their systems.

In Bright Agrotech’s aquaponic system, we already have these great hydronic coils that deliver hot water from our boiler system to our heat exchangers bringing warm air into our vertical farm during the cold months.

Making the decision to heat our fish tanks with these coils was not only inexpensive, it only required installing a three-way valve onto the tubing. I think it only ended up costing us a couple hundred bucks in tubing. At the end of the day, it allows us to heat our fish tanks with practically zero additional input from us because of the low tech nature of it all.

While this works well for our application, grower’s need to design and choose their heating system based upon what resources they have available.

Author: Chris Michael

Chris Michael has the best job in the world. Everyday, he gets to interact with innovative and passionate vertical farmers and equip them to cultivate a brighter future of food.

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  1. I’ve gotta say, you guys keep hitting my inbox with interesting topics. Phosphorus last week was excellent.

    I’m in the middle of converting an old barn in upstate new york for aquaponics and its pretty inspiring to see that you folks can weather the winter out in Wyoming!

    Post a Reply
    • That is so great to hear, Duncan! The last thing we want to is to clutter your inbox with uninteresting and irrelevant topics. That sounds like a really neat project you’re working on. We would love to see photos of the build out if you have them.

      Post a Reply
  2. Nate you demonstrate the KISS (keep it simple stupid) method in so many ways. It keeps it less expensive too. Thanks

    Post a Reply
  3. I guess the topics Nate talks about and makes it simple helps us a lot. I am eagerly following the nutrients series.
    I guess this kind of organized lecture series is rare. Great job and please continue to keep it free.

    Post a Reply
    • Thanks for the feedback, Agradut! We’ll do our best to continue producing free content, but remember we can only survive as long as we continue to sell ZipGrow towers! Help us spread the word?

      Post a Reply
  4. what about bacteria at low temperature? there are ranges for the good health of bacteria? thank you

    Post a Reply
    • These types of bacteria can remain in a healthy state at a fairly wide range of temperatures.

      Post a Reply
  5. I’ve followed just about every piece of info that y’all have posted thus far and have learned a tremendous amount of how to sustain a healthy aquaponics system; me and my family have already embarked on a journey of our own. Greenhouses are up and ready for system build. But I did have a question about the shipping end on the commercial side of aquaponics. There is not much info out there on packaging: how or where to get it; in order to distribute to local restaurants. I would like to have something to put my logo on but not sure where to look. We are planning to start with lettuce. I have seen a few styles but again not much info on the subject. I appreciate all y’all have done.

    Post a Reply
    • Hi Tyler,

      Sounds like you’ve got some exciting times ahead. Regarding your packaging question: Do I assume you’re not growing with ZipGrow towers? If I’m mistaken and you are using them, you could offer restaurants a live tower delivered directly to them. That would ensure freshness and some creative marketing angles + a competitive advantage over their competition with our “Right Now Fresh” produce.

      Whether you’re using towers or not, it’s best to ask the local restaurants you’re growing for and distributing to how they would like [cut or living] greens delivered. They may say a box or a crate is fine or they may decide they’d like to you invest in clamshells or other plastic packaging. Unfortunately this type of option requires an additional cost to you the producer. Giving them a Spring System basin to hold the living tower of lettuce you deliver would likely be ideal for you and them as they get the freshest stuff [see: more nutrients, more flavor] for their customers and you drastically reduce your post-harvest labor and packaging costs.

      Just some ideas. Best of luck.

      Post a Reply
  6. How long does it take to to see ammonia in fish tank when cycling in cold weather? I have had my 275 gallon tank with 12 goldfish for over two weeks and no ammonia has been detected.

    Post a Reply
  7. I plan on building a community system in Star Vallley, WY (most likely in or around Afton). I was contemplating using a Walipini greenhouse in order to retain as much heat as possible. My wife is from Afton and I am from TX so I don’t know the winters but I hear they are pretty cold, well below freezing and even below zero. Would I be sacrificing valuable light in such a setup or is it worth it to save on heating costs and having a more temperature stable environment?

    Post a Reply
    • Hey Shawn,

      Great question! Folks from other states really can’t contemplate just how cold it gets here throughout the winter and therefore you’re smart to think about your heating costs. That said, a Walipini setup will be much more energy efficient (if you can dig deep enough in the frozen Wyoming soils) and you can always add supplemental light if need be. I’d imagine the light quality would be poor enough that you would need it.

      Post a Reply
  8. I have a question… What would cause your system to revert to 0 nitrates and 0 nitrites? 2 year old system and I was thinking that I didnt get my heater installed in time and the beds got too cold… I have been keeping the water at 75 deg for the fish… We had 3 weeks where it was in the 20′s and maybe 30′s inside? I’m lost an no one else has any reason for this nor can I find anything…

    Post a Reply
  9. Love the wood burning furnace setup. I’m also remembering Dr. Story showing off a makeshift geothermal setup in one of the videos on a greenhouse setup. Maybe something like that could help with temps a little if further refined.

    Post a Reply
  10. Hey Chris,
    quick question while were on the subject of greenhouses lately. I’m from West Texas and i’m working on a small scale system, but I am actually looking to expand my operations to a little bit bigger commercial scale. my question though is that I’ve not seen much information on large greenhouses and am trying to get some info on good places to obtain them that is reasonable and dependable, any suggestions?

    Post a Reply
    • Hi Tyler, how large are you talking? Depending on the style you’re looking for, you could find some solid hoop house kits on Greenhouse Megastore dot com.

      Post a Reply
      • Chris,
        appreciate the tip that’s what I was looking for.

        Post a Reply

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