That is a good choice.
I would also consider a vieja....they are agressive.
(is it just me or are a lot of old threads popping up recently)
I've noticed the same thing over the past few days...
but the pic of the Nandopsis Haitiensis and my subsequent Google search, show it's a good thing to stir older post up now and again. That's a nice "dinosaur fish"





I am actually thinkin' of getting a RD myself. I've got my Silver Aro moving into a 120 gallon so the 75g he is in will soon be vacant.