Ive been told that they ought to be fine together, and that it is unlikely the dats will fit in her mouth due to height. I have plenty of tanks, at any rate.3" is too small to be hanging around with large polypterus...
The 9.5" Lapradei will probably maul the 3" datnoids.
Polys dont "maul" anything per se. They either eat things whole or ignore them. Every so often they snap at one another on accident. They definitely cant eat my 4" clown loaches.
Happy turkey day!