Payara

[Raskolnikov]

Well if they were bought wild, maybe they can grow larger in an aquarium as compared to captive bred?

They are not captive bred.

 

[StreetCypher]

Even with my pond condition? they will still die from it?

Well, if they're 18" and still living in your pond then you're doing something right.

I'd still love to see pics though, maybe your estimation is off from eyeballing the fish from above