Even though khuli's are often great escape artists (either accidenially or on purpose) I have had a group of about 6 striped and 2 or 3 brown/ black (never sure of exact numbers as they only really come out in the dark and I only get to count them properly when my tank has a major overhaul), these ones are thriving in a tank with guppies, bristle nose catfish, sparkling gouramis, 1 lizard fish and now some recently added cherry shrimp. My tank doesn't have a lid and after a good two years of them residing in the tank I have not had any surcides or accidental leap outs. But then mine have quite a lot of live plants and some timber they can burrow under as well as other pipes and things they like to hide in or under.
They are great loaches and apart from being near impossible to catch, are never a bother, they really do like being in a group and I think the group situation might be another reason mine are so happy to remain in thier tank.