Can you post video of this perhaps? Kuhli loaches are really awkward swimmers. Mine sometimes swim upside down to snag food floating down or under plants(though not typically when just swimming around), they love to swim in circles, and curl up in places and just wiggle around. It's kinda what they do...since I can't SEE what yours are doing, I can't even tell you if it's normal or not...
Have you checked your water stats to make sure there is ZERO ammonia? Ammonia can cause some nasty pain and kill them, even a little of it. Have you been spraying anything near the tank? Sometimes if an airborne spray like cologne, fabreeze, anything that is airborne with chemicals like that stuff, it can sometimes cause fish to spin and act awkwardly, it'll outright poison them if it gets in the tank. Some are more delicate to it than others, and though loaches don't typically go near the top, should they during the time something is in the air it can affect them. Eventually it will kill them if kept up. Sometimes they recovered if it's taken care of and the place is aired out though.
The temp being too high can sometimes affect them oddly too. They seem to dislike it past 80 degrees or so. Yes, some can handle it, but if there isn't enough oxygen in the water they cannot and will act weird because they're suffocating, some may try to stay at the top until they no longer can and then the mess gets worse, they lose the ability to function properly since they have little to no oxygen supply.
On another note: please don't flush animals you don't know if they are dead or alive. Horrible death, that. If the shock doesn't kill them they can potentially survive in the filth for days/weeks until the toxins and ammonia literally melts them away. It's a truly awful way to die, it'd be a lot more humane to take them out and smash their heads than it would be to flush them. When I am unsure of an animal I usually put it in a container with tank water, a bubbler and some live plants if I lack a QT tank.
