Could you put a black kuhli loach alone in a 5 gallon tank?

You cannot put a black kuhli loach in a 5 gallon tank at all, they need a 10 gallon tank at the very least. The maximum size that this loach gets is about 4-5 inches, so a 5 gallon is out of the question. As far as I have read, the black kuhli loaches like to be in schools of about 3-4, and you wouldn't want to have them alone, since the are community fish, they can go with platies, most tetra's, mollies, sWordtail's, and small plecos. they just can't be alone or with fish bigger than them that will eat them.

hope this answers you question.