While Stardew Valley offers players a wide variety of fish, Legendaries are the most valuable trophies, and Mutant Carp is one of them. Since Mutant Carp is one of five members of the first generation of legendary fish, players can catch just one of these carp for one save or one for each player when playing cooperatively. High rarity makes it a desirable catch for any fisherman, and fortunately, it is relatively easy to catch.