I searched a bit before getting one and read that some keepers called them "lazy" and "boring."
As for agression. I keep it with one other fish that hides so I have no comment towards that.
It's my kind of cat.
I think it's safe to say that if it has a mouth it will eat something. It's a predatory cat so anything the size of its mouth or smaller is at risk.
I had a Lima eat an Arrowanna of equal size already and they are not considered agressive.
Anything is possible. Choose carefully but don't be surprised IF something happens.