This is my catfish tank... iced over and buried in snow. Yes, we had snow in Elgin and three days of cold that did not get above freezing. But eventually the sun came out and everything thawed out and my catfish survived. They are pretty hardy. Now if they can survive the Texas heat this spring. Hopefully, they'll be eaten before the summer and I'll replace them with Tilapia.
I have also managed to keep my tomato plants alive. I try to start seedlings in January in zip lock bags over our wood burning stove. Germination happens fast. Then I put them in cups and move them to the greenhouse. Normally I don't heat the greenhouse but this winter has been so cold I taped a piece of clear plastic over my shelf that the seedlings sit on and put four clip on lights underneath the shelf. I have a thermometer that reads the temp in the greenhouse and an extention that reads the temp under the plastic tent. The coldest it got under the tent was 34 degrees F so everything has survived so far. Another month and I will set these little babies out in the garden.
These are the plants growing aquaponically in my greenhouse. They are doing really well and I noticed today that my first head is forming on a broccoli plant. Pretty soon we will have some veggies to harvast, kale, lettuce, chard and broccoli. I even have a tomato plant that I took a cutting of and stuck in the gravel. It rooted and has been growing and I have a tiny bud on it. Maybe I'll get some early tomatos.