Not sure if you know this but pacu are highly vegetarian diet in wild. Try some zucchini, carrots, broccoli stems (avoid flowerets), nuts like Brazil nut, almond, cashew, walnut. Just be aware with most of these natural foods it will contaminate your water fairly fast especially it it leaves chunks of them behind. If you aren’t already doing this I would also suggest a good veggie pellet like nls algaemax to get some veg in the pacus diet. Often when you feed a veg eating fish an all or high protein (meaty) diet it can cause constipation and can shorten lifespan of the fish.
whatever you put in the tank, the pacu will eat it. Doesn’t mean it will be good for it. It’s up to us to know what they would typically eat in the wild to (hopefully) simulate that as much as we can.
as for the bass there is a whole other section of threads, and some stickies that are helpful as to how to wean them onto pellets. They can be super fussy, but it is usually easier with a teacher fish like the pacu that eats everything. My first batch took a long time to get off of brine shrimp, they wouldn’t eat anything else not even blood worms. So eventually I had to thaw out brine shrimp, crush up pellets, mix it all together and refreeze it and feed chunks of that before they would take pellets. Just be patient and don’t give up, and you will get them there.