Freezer Fish Tank

Freezer Fish Tanks

Aquaponic Freezer Fish Tanks Well, the verdict is in.  

After six months of research and experimentation and 18 months of in-service testing, I can confidently say that using freezers as fish tanks works like a charm.  You can find the stuff you need to build one here.

At this point, they have withstood 16 months of submersion including draining and refilling multiple times, with zero leaks. They show no evidence of sun or any other kind of degradation and I expect them to work for decades more.

Am I getting ahead of myself?  Sorry…

Why Would I Make Fish Tanks Out of Freezers?

Think about it for a second.

Manufacturers have been designing and improving them for 200 years, with the single goal of maintaining a stable inside temperature and humidity with minimum energy input. In our homes, they operate at a 75 degree temperature difference from the air around them, and maintain this for $50 per year in electricity use.  A truly remarkable device!

OLYMPUS DIGITAL CAMERAWe think of them keeping the things inside cold, but there’s no reason they can’t work in the opposite direction. In fact, they do.

Growing in cold weather, managing your heat loss means the difference between spending $1000 on winter heating and spending $100. If you read up on Aquaponics Principle #2, you’ll know why. Where I live, those numbers are real.

There is no single improvement to your aquaponics system that will save you more money than converting from open-top fish tanks to mega-sealed-and-insulated tanks like these.

Why Don’t I Just Make a Kit Myself?

You’re welcome to try 🙂

I’m an engineer by day, and finding specialty products is my bread and butter. Even so, I can tell you that it took me months of searching and dozens of conversations with paint store reps, suppliers, manufacturers, and industrial end users to find products that met these three criteria:

  • Food Safe:  This product is compliant with FDA Seafood regulations and NSF potable water regulations. Fish bio-accumulate many heavy metals and toxins. Painting your tanks with boat paint, pool paint, or any other kind of non-food-safe paint is risky.
  • Submersible: There is a difference between paint which can handle rain and puddles, and one that can handle submersion under 36″ of water for years on end.
  • Sticky: The inside of a freezer is one of the most difficult things in this world to paint.  They are very well-designed to be nonstick. Finding a coating that both sticks and does not degrade the metal walls of the tank proved a real challenge.


No freezers handy?  Here’s how you can find one.