No, you can’t keep just one kuhli loach. Even though they’re not schooling fish, kuhli loaches are social creatures. They love company and feel more comfortable with friends.
In fact, if kept on its own, a kuhli loach will be too afraid to explore the tank and will remain in hiding. It’s recommended to keep a small group of at least three kuhli loaches.
Alternatively, you can keep other peaceful fish and aquatic creatures to keep your kuhli loach company, for example: