
I placed them in two tanks containing hillstreams with mixed results.
In one tank the gastros (ctenocephalus and oscellatus) as well as the L. disparis have worked the stones over well. Unfortunately,the many shrimp (bumblebee, cherry, amano and neocardina) also seem to like them,too. I placed the rocks in good current flow to keep the shrimp hoard off them as best I could and that seems to help.
In the other tank, the chenis checked out the rocks quickly and did some grazing but not as intensely as the gastros in the other tank. The two gastros (oscellatus and scitulus) haven't given the rocks any notice. The scitulus is strictly an algae eater as far as I can tell and has never been seen eating anything else, but he has not grazed the rock despite being within an inch of it.
So, while the rocks in one tank have been cleaned of algae the rocks in the other tank have barely been touched. Very odd.