Well, how about a different species such as any of the smaller Rainbow fish? How about Dwarf Cichlids such as Rams or Apistos? How about Sparkling Gouramis?
IME Jewel means Jewel Cichlids, not anything I would want with the smaller fish you currently have. I kept Jewel Cichlids with larger fish (about the same size or larger) and even then they were a bit pushy.
As a general guide do not mix larger and smaller fish. If the larger is twice as big and a known predator it is highly likely to eat the smaller fish. Even fish not normally predators can eat fish that are 1/4 their size.
So... 1" Rummys or Cards should not be mixed with fish larger than 2" (if the 2" is a predator) or larger than 4" (if the 4" fish is not normally a predator). Look at the mouth size, most predators can open their mouths REALLY WIDE.
A 4" long Kuhlie Loach does not really fit that general guideline. Their mouth is so small they are not a threat to 1" or even smaller fish, and they are so thin that they are easily eaten by predators that are almost the same size they are.