but if they can get as bigg as you all say guess I will pass

They are amazing growers... they grow about as fast as Koi in their first
years.

I bought 10 of them 5 years ago (they were less than an inch) and I have 9
left (heron :-( ) and they are all about 12" in size.

They are supposed to be school fish so you'd have to buy at least 5 to make
them happy.

A nice side effect of keeping them is that they always live at the surface,
and that seems to invite the koi to do the same. I had to put road signs in
the pond to aid them to go to the bottom from time to time ;-)

Their color is incredibly bright when they are healthy, and when you look at
the pond from a distance, they are the most eye catching color wise.

Their feeding habits make koi seem to anorexic & lethargic My wife
calls them "the sharks"...

You do have quite a large pond IIRC, so yes, I think they would be a very
well worth add-on.

Theo