I suppose it's possible. Someone might have harvested the fish from a Wilderness that did have seawater.

There are a few places in the scrapyard that actually have slabs of walls. I've scavenged some insulation from that. It's a pretty piecemeal method, but better than nothing.

[He chuckled a little, amused at the suggested possibility.] No, but I wouldn't be surprised if that happened at some point. These were ordinary pieces of food shaped like real people in the Sphere. It was less than appetizing.