Comments on the fish you initially listed:
Red Tailed Tinfoil Barb is doable in a 125g, assuming this is a 5-foot (or 6) tank. You can read more on them in the profile, click the shaded name. A group of 5-6 on their own, they attain 8 inches.
Denisons barb would also work, a group of 8, these attain 6 inches; again, more info in the profile.
Hillstream Loach is actually a good match with the Denisons Barb, both require lower temperature and moving water for oxygen. There are some ideas for aquascapes in the profiles. My only concern with combining the loach with the Tinfoil is they might get eaten. Otherwise, also a good match for same reasons.