The rare drop chance of getting one of a fishable fish was lost.
Also Looting increases the quantity of raw fish or prismarine rather than altering the drop chance, and the Elder Guardian sponge drop no longer requires a player kill. These could easily have been intended changes though.
Linked issues
Comments 3
This seems to be an issue again (Minecraft version: Minecraft Java 1.16.3 - latest version, 14.09.2020), My guardian farm uses fall damage and alternatively I use a looting III sword, but neither method gives the rare clownfish/pufferfish drops. I got 2 doublechests full of cod, so far.
I think I remember a long time ago, when I built the farm, I killed a guardian that had a pufferfish drop. Are guardian drops from guardians that are spawned with the world on chunk creation different from those drops from guardians that are spawned later?
Confirmed but this was the case even before the snapshots in 1.8.8. I'd say this is WAI.