Tropical Pacu not eating

It noticed something too. Fish seems to tend to pile up on the right side of the tank, and refuse to swim anywhere again.

I've noticed this bug with pacu pathing AI, and I noticed some oddities, and a workaround. For some reason when a build is queued where the pacu is pathing to or currently is, they will get stuck in that spot. Sometimes they will get stuck in a spot that a building was just deconstructed as well, even piling up 10+ pacus in a single tile with none of them moving away to eat or wander.

A way to force them to move again is to queue a build order where they are stuck. If there's a ladder or something in the way, deconstruct it and queue a new building in that tile and they suddenly all start moving again.

Update: I just encountered this bug again, with a huge stack of pacu all piled up in one tile. They have a massive 69x3 pool to swim in, and there are 15+ pacu stacked up in one tile.

Saving and reloading caused them to break up, but I noticed something odd. Once I reloaded the save, the pack of paku dispersed, but 8 of them died all at once. 

I'm wondering if this bug has something to do with the AI when the critter reaches maximum age? Other critters will still wander around for a few seconds even after being zapped to death by dupes. Though this doesn't explain everything, as there were several pacu frys and other pacu of different age in the pileup.