diff --git a/2d_spots_in_fibers.py b/2d_spots_in_fibers.py
index 53df4a20310c7de8db1e03ee238ccd16312061f3..41ca9e458357aad65807cfbda249bfbd13ce723c 100644
--- a/2d_spots_in_fibers.py
+++ b/2d_spots_in_fibers.py
@@ -765,7 +765,7 @@ canvas.close()
 fiber_label_imp.show()
 
 # threshold DAPI channel and convert to binary
-dapi_channel = BFopen_image(path_to_image, dapi_channel_number, series_number, z_slice_number=dapi_channel_zslice)
+dapi_channel = BFopen_image(path_to_image, dapi_channel_number, series_number)
 if threshold <= 0:
     threshold = get_threshold_from_method(dapi_channel, "otsu")
 dapi_binary = convert_to_binary(dapi_channel, threshold)