Is Fish Part Of The Balanced Desert Breakfast?

I had a coworker watching Trigun over the weekend. There's a point at which Vash explains why he passed of the reward for recapturing two members of the Nebraska family. One of the reasons is that, since he essentially saved the town, the kindly old lady who owns the diner they're sitting in has promised him all the salmon sandwiches he can eat.

Which sounds great until I remember they're on a desert planet. I suppose the salmon could have been brought along in the great ships they used to reach this planet, and that they could have survived the rough landings like the humans did. But salmon seem like a very inefficient food source to maintain on a desert world, where people are so heavily dependent on those plants of theirs.

Maybe Knives was right about humans being worthless garbage that should be exterminated.

I'm not really clear on the limits of what the plants can do. They're a massive energy source, so maybe they have a machine that can create salmon flesh, ready to eat, without needing to make an actual fish that would require additional resources to maintain?