biggest one I've seen was 9.5"
they grow slowly so if you get a small one it'll take forever to get that big.
if you get one to 7-8" that's pretty big already.
if you want a big one better off to get one big to begin with
some one has a 10.5'' one on p-fury but cant remember his name, trust me its the fastest p in my opinion , look at its shape bro its a submarine P hahahaha
if i had run into it before i got the rhom i would've but i'm enjoyin the small rhom too much to get rid of it yet. Lil guy has been more social then my shoal ever has been
I have a 6" maybe 7" BME. Honestly I'm not real impressed so far. Hangs in corner or hides all day. Definitely no rhom or Mac!he's a awesome looking piranha just not aggressive yet.