Before jumping the gun... what species is this loach, exactly? Common names are misleading for many fish as they are only common to the people using them. But I am suspecting you may have Botia striata which is often called the Zebra Loach, and not the much larger species of which I can't remember the name at the moment.
If your fish store said 4 inches, and making the assumption they may know what they are talking about, the loach is more likely Botia striata and this loach attains 3.5 inches (9 cm) max. It is well suited to a 1 metre tank, in a group of at least five, and is fairly peaceful for a loach. I have twice had a group with no issues with other fish, though I would not combine it with other loach species.
So, if you like the loach, get another four or five to make a group of five or six. Make sure you have lots of wood, and I mean, lots. Several chunks of wood that has tunnels and crevices is absolutely essential for this or any other loach. Artificial decor like PVC pipe and such can work too, but I think real wood chunks is more natural and the loaches do love it. Each loach must select its own "home" and this provides them the opportunity.
I don't see any issues having this loach with the other fish mentioned. I'll add a photo of B. striata, so you can compare with the loach you have.
Byron.