How big is the biggest datnoid?

[Hybridfish7]

I have seen videos of some HUGE ones, and as far as seeing what their cousins are goes, with my sparse knowledge of the family, I'd assume they're oddballs, so I don't have too much of a guess on their growth. Could someone fill me in?

 

[Kelly_Aquatics]

They grow very slow and max out at 24 most likely 18 in tanks though