i had two, the smaller died very soon for lack of food, i think. From what i observed, they are poor algea eaters when compare to either ottocat or snails, since they can't scrape up algea growing on the glass. They do eat hair aglea growing on leaves of plant readily. When hungury strike, they occasionally search through the gravel for leftovers.
this is personal experience, since you asked for it. as for wate condition, check loaches.com.