Regarding the clown loach/loaches, I am going to offer quite different advice. Namely, do not get more. First, assuming this is a 5 or 6 foot tank, it is not sufficient space for mature loaches that should be in groups greater than six, but this means an 8-foot tank is bare minimum. Looking ahead, this is not going to work on this aspect alone. Second, the group of loaches must be added at the same time, so a natural hierarchy forms. One loach will be the alpha, and the others will know it. This is a basic inherent nature of all botine loaches. [Botine is my term for all species of several genera that are basically "loach" shaped, it has nothing directly to do solely with Botia species.] After the considerable time that has elapsed with this clown on his/her own, adding others (which will also likely be smaller/younger) could cause the matur loach to decide they are not welcome. That will not be very nice to witness. This is probably a situation where it is kinder to the fish to leave well enough alone. I certainly agree that being the lone loach is a very serious detriment to the fish, but this in not reversible so it may be best to leave well enough alone.