temper and feeding wise, they will all get along fine. however pacu will enjoy fresh fruits and veggies more than other fish usually, since its their natural diet. however, if you honestly plan on keeping these guys, you WILL need to upgrade that tank to.....oh, i dont know.....10x the size it is now
not sure if you realize it or not, but every fish in your tank has the potential to reach over a foot long. the pacu and arro 2-3 feet. ive seen a few large, quite beefy oscars as well that arent anything to scoff at.
a pacu can and will reach pushing 3 feet, and weigh 40-50pounds EACH easily. i know this personally, since i have a 2 footer right now. pacu in all honesty, is generally a very BAD choice for most fish keepers. the hype about their size, and power ability, arent hype, their truth. you honestly need to think about this seriously now, before they hit their growth spurt and baloon up to a foot and a half.
if you get passed the tank size thing, oscars, bloods and pacu will generally get along with most cichlids. their more than happy living with mtes that wont bother them, yet they can hold their own if it comes down to it also. despite the reputation oscars may have, they are more often than not a lazy fish who dosent want to be bothered, and just loaf around the tank. pacu are nothing but tetras on steroids, minus the roid rage. absolute gentle giants of the aquarium hobby. and parrots can be nasty, but since they have a deformed mouth and cant bite, will generally just chase fish around, and not be extremely nasty in my experience.
hope this helps some
