Just need to jump in here, Ive seen many yoyo loaches get 5 inches+. They get very aggressive especially to bottom dwellers, and as they mature in low number groups they will kill eachother till there is one left. The only botia type loach I can ethically recommend is sidthimunki, because it is captive bred in large numbers, but for a peaceful one they still get nippy. For riverine I would recomend corys, ancistrus, maybe hypancistrus, buffalohead cichlids (aggressive), neon tetras, white clouds, danios, peacock gudgeons look like they are riverine but arent, checkerboard barns are pretty small but they are nippy once settled and dont school well. For nano tank cpds, kubotai rasboras, and I would do neocaridina, maybe MTS and pick them out as they overpopulated. Bee shrimp are a bit more riverine though but they like softer water. Obviously not everything listed would be compatible so it's just meant to give ideas. In my opinion hillstream loach tanks are way played out, plus they arent sustainably caught.