Homesteaders and others living off grid often face a variety of challenges that others would never even consider in their day-to-day lives. Making sure that your power supply is maintained, that you have access to clean water, maintaining a garden to ensure you have an ample food supply, and probably hundreds of other things large and small.
Of course, one challenge is finding ways to add variety to your food supply that is self sustaining. Many turn to gardens or greenhouses for fruits and vegetables, and raising livestock like chickens, goats, and more, but that will depend on that land you have and it can be expensive to properly care for a large number of animals. One possible method to add some protein, and help with produce, could be an aquaponic system.
By charlie vinz from chicago – portable fish farm, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=7913728
Such systems can be a lot of work, especially as you are learning and trying to get the right balance between your water, fish, soil, and plants. But once you get it all fine-tuned, you can have a pretty regular supply of vegetables and fish, all with minimal waste.
There are some fairly fast-growing fish, such as tilapia, perch, or even trout, so you should do some research into what may work best for you.
The waste created by the fish fertilizes your vegetables and uses less water to grow food than more traditional gardening. Such a system will require tanks for the fish, pumps, and so on, but the initial costs are offset by the food you are able to produce.
Aquaponic systems are an interesting option and perfectly suited to those who are living off grid.