I am almost done setting up my 180gal tank. I will be transfering my 6 clown loaches from there current smaller tank to the larger one. I have been keeping them in a bare-bottom tank that has lots of driftwood. I want to put gravel over half of the new tank's bottom but some people have told me that clown loaches shouldn't have gravel. Is this just the opinion of a few people or is gravel really a poor choice?(I don't want to use sand)