|For other examples of fish in the Fallout series, see Fish.|
Fish survived the nuclear devastation of the Great War in a relatively unchanged shape, at least in the Potomac. The fish that live in the river are not edible, as they are highly irradiated and heavily contaminated with mercury. While the fish adapted, humans who try consuming them die a terrible death.
- ↑ Rivet City terminals: "Fish poisoning: Less of a problem nowadays, but occasionally someone finds a fish in the river and is dumb enough to try to eat the thing. Radiation levels spike and mercury poisoning drives most victims crazy. No cure, but at least people nearby get a reminder not to do it."