Plecos Aggressive Fish??

ah . . . no. i . . . did you just compare neons to piranhas? 'cause . . um . . . well . . . no. :) actually the behavior that you are talking about in piranhas is 'caused by starvation, not the lone psycho fish.
 
some plecos are agressive though and not only to other plecos but to other fish. Some will atack discus and angel fish my plecos from before use to atack my oscars and they would even go on a high speed chase to catch a goldfish I would often find them latter on eating the goldfish they were chasing. So it depends on the pleco and it was a common pleco not a carn but a veggie eater so never underestimate the power of the PLECO.
 
GER1023
I'd always heard that as; "I see I see said the blind man as he picked up his hammer and saw."
:)
 
I had a pleco that once it reached 6-7" it started getting very aggressive. It attacked and killed 3 adult angels that I had. It didn't take me long to turn that fish back in.

This is just my expierence I'm sure others have good ones. Like all the other post each fish is different.
 
I no longer have my pleco....He was pretty peaceful but would have gotten too big, and it also saved any accidents that might of happened.:) I returned him to the LFS where I got him.
 
AquariaCentral.com