BTW, most people who've kept Nandus indicate that the max size (8 inches) listed in fishbase is too large. Most don't get much larger than 4-5 inches in captivity.
Behaviorally, they resemble datnoids. They aren't aggressive. Also, they're purportedly more difficult to get weaned off feeders than are datnoids. I've kept them in the past, but my endlicheri bichir ate them.
I have a 5" Nandus Nandus in with the Dats. He mostley sits in the plants or under rocks. He only swims during the night and late evenings. He's completley MELLOW. Now I even have a Leopard Cep. about 3.5" and they just sit around all day in the same hole together. He doesnt even swim when food is dropped in. He waits for it to swim up to him then he eats it.