My loach will get to be about three inches at the max -- they are supposed to be happier kept in groups, and certainly when they had a group of them at the LFS they looked much happier. But they only had the one left

I had wanted three, but my tank didn't cycle before they were bought out. And they don't know when or if they will get any more in -- apparently it all depends on what their agent in CA picks out of the imports to send them.
I plan on building up a shoal of the minnows two at a time over the next few weeks -- that will let me keep a close eye on the water conditions, and possibly let me over stock the tank slightly if the bio-filter can cope with it. Eventually I'd like six minnows and the loach. 15 inches, which is high for 10 gallons, but they're pretty low
bio-load fish - skinny omnivores.
I'm really iffy on the health of the loach -- I've spent a lot of time over the past couple of months watching these guys at the LFS and this one is just not acting like I've come to expect them to act... He swims oddly compared to the way the others swam, and lists slightly to one side.
Another reason I'm limiting myself to the two minnows right now -- if the loach is sick, I'd rather minimize the other fish I'm exposing to him. I figure a week should give me a good length of time to observe him, and figure out if this is just this fish's personality, or something else.
The one good sign is that the loach is eating like gang busters when I drop a pellet for him.... so if he's sick, he's not real sick yet, and getting out of the crowded LFS tank is probably a good move.