Look into blue panaque
As far as I know they are.
would you risk a $600 fish (the "stripy royal" I posted) by giving it only wood to eat?
Would you risk feeding a $600 wood-eating fish something besides wood? Panaques fed protein foods are said to die at random.
Besides, all the wood they get would be covered in algae, snails, and all the usual natural muck that grows on submerged wood outdoors, anyway. Pretty sure that has the bases covered.
Can't afford blue panaque, obviously. Presumably papa panaque can't be found at LFS for 40 bucks like L191 can...