I love em'. They need driftwood in their tanks and can actually grow and thrive on just driftwood. They're mainly herbivores and are hearty eaters. Cucumber, parsnips, zuchinni, carrots, sweet potato, etc etc. Royals will eat it all. They get territorial when older with other Royals but it takes them years and years to reach their 18" max size. I've never seen one that big. There's also the green/black striped L191 Royal (called Dull-Eyed or Broken Line Royal). PlanetCatfish says they get 9-10" max. I've had mine 2 1/2 yrs and he's gone from 3" to 6 1/2". My favorite Plec.
They're all wild-caught. There's no documented captive bred Royals.