I added a custom collision type named fish, added this type to fish capsule and to blocking volume, set Trace Distance with values between 1 and 100. This is the result Screen Recording 2025 10 31 090725 , the fishes are all block to same position. I increased water column to bigger one and the result is the same.
Ok, I think I see whats happening here. Thanks for sharing the video, it really helps to see whats going wrong.
Open the “BP_NPC_Fish_Base”
(Blueprints > NPC_Fish > BaseClass folder)
Find this area after Tick (See Image)
When a fish gets within 1500 Unreal units of the current WaterTarget they switch to a new one. it looks like all your water targets are all within this area- so they just keep switching to a new target and don’t move anywhere. Try lowering this value to like 200, Save and compile- and test.
Let me know how this goes, you may also need to scale down the Fish as the water area your working with here is quite small.
Same result with 200 and 100. Screen Recording 2025 11 02 161651
what is their behavior if you get rid of the blocking volume? do they move toward the Water Targets? or go up into the air some distance above the water targets?
also be sure those Water Targets are not inside the blocking volume as well. they need to be reachable. Also when you scale down the fish be sure to scale down the collision capsule. The Fish is looking like its getting constant collision on the capsule.
UPDATE- I think i see a few changes that I could make to make the system more flexible. I’ll be submitting an update later today, I’ll update this post when I do.