FishNoStub

A small modification module that fixes the problem of fish completely stopping movement in Minecraft, related to the official bug MC-182763.

Compatibility: Minecraft versions 1.17.x-1.20.x for Fabric (possibly Quilt) and Forge.

How It Works

Fish in the game have a special artificial intelligence system that scans nearby individuals and randomly selects a leader and followers. Then the follower fish begin to follow the leader.

This mod fixes an error in the FollowFlockLeaderGoal code by adding a check: whether the nearest fish is a leader or not. If not, it is added to the follower list.

When a leader gets into the follower list, a problem arises: the leader fish stops and ceases to move along with its followers (forever!). This can only be fixed by hitting the fish or switching to survival mode and swimming close to them.

Additional Fixes

• Changing the entity predicate using EntitySelector.NO_CREATIVE_OR_SPECTATOR instead of EntitySelector.NO_SPECTATORS in the avoid entity goal
• Setting the checkNoActionTime parameter to false in FishSwimGoal to eliminate fish getting stuck in one place
• Decreasing the schoolSize value of the leader fish when a follower fish dies

Performance Impact

The mod does not improve game performance and has minimal impact on system operation, especially regarding fish behavior.

Installation

• Install Fabric Loader or MinecraftForge
• Copy the mod file to the mods folder

Creation Story

The author was working on the Fish of Thieves project, studying the FollowFlockLeaderGoal code and converting it to work with the Brain system.

When displaying debug information above an entity, it was discovered that a fish with a schoolSize=8 value had the property isFollower=true and a leader, which is technically impossible. This observation became the starting point for creating this mod.