I had a giant pacu for 4 years, sadly he died durring Hurricane Andrews in south Florida.
This was no mere fish but was an actual pet and odd enough, a friend.
I had suffered from intestinal cancer and confined to home for a year in which time I got to know this pacu quite well. I named him pug because he was very timid at first and rammed his face into an aquarium rock, removing a big chunk of skin from his upper mouth. He didnt seem to suffer it much but I know it pained him.
Anyhow, I eventually could stick my hand into the water and rub him, he would even swim up to my hand and brush against it as if he wanted to be pet. He seems to have loved me quite a bit but didnt care for my wife much, making here sorta hate the poor guy.
When she got near the tank he would splash water hard enough to knock the top off the aquarium and scare the **** out of her (I thought it was funny, she didnt)
He wanted to eat anything I was eating and would do the same water splashing till he got it.
One day I was tossing m&ms unto the air and catching them in my mouth as he watched. Soon he began splashing the water and letting me know he wanted one.
I dropped it into the tank and it went to the bottom as he watched it sink. He began splashing water again.
This time I threw the m&m into the air and it went into the tank.
The guy darted after it and seemed to have swallowed it, then to my surprise he spit it out and caught it between his teet (he had teeth) and turned to look at me and shook his head as if showing me he can catch them too.
He was 24" long and from bottom to dorsal was 18 1/4 " tall. Very large indeed.
He would eat spagetti noodles but only if I held it up while he gulped it down.
They are very smart and given proper attention can easily become a very amusing pet.
I just wanted to share this story with other pacu owners.
As stated here, he will grow to be very big so if you dont have plans for such a big fish, dont get one. For one you may become very attached to it, number 2 you might find it difficult in locating a new home for him.
Here in Florida many have been put out into canals and this
can greatly damage the eco system.
Most recently here in South Florida, python owners have been releasing their overgrown and burdoning pythons into the everglades and a battle rages between alligators and pythons.
http://www.mongabay.com/images/external/2005/r1893035670.jpg
The snake ate the large alligator. It is thought other alligators attacked trying to save their own kind and the snakes belly was ripped open and its head was missing.
Close up images of this scene show bite marks on the rear of the gator as if another gator had attemted to pull the eaten gator from the ripped open snakes belly.
http://www.sciencedaily.com/releases/2008/05/080520131750.htm