Well mine wouldn't work either then since the BTB Loach get upto a max length of 1ft. They are the largest and most aggressive members of the Botia Loach family.
I thought it was about the fish, in question, being under 4in not a max size of 4in. Well if it's about max length I think I'll go with this guy instead. He was a twintail halfmoon plakat betta.