Key to the species of Quietula
by J. Van Tassell

1a	Seven dark, somewhat diffuse saddles along dorsal margin from head to base of caudal fin; caudal peduncle without dark spot or "Y" marking; anal fin generally light colored or with a few scattered melanophores in membrane; dorsal base of pectoral fin without a dark spot............................................................guaymasie
1b	No dark saddles along dorsal margin; caudal peduncle with a dark spot or distinct "Y" shaped mark; anal fin generally dusky to dark with scattered melanophores present in membrane and along fin ray elements; dorsal base of pectoral fin with a dark spot ................................................................................................. Y-cauda