diff --git a/python/pfs/drp/stella/datamodel/pfsFiberArraySet.py b/python/pfs/drp/stella/datamodel/pfsFiberArraySet.py
index dd003cd86..f7441b661 100644
--- a/python/pfs/drp/stella/datamodel/pfsFiberArraySet.py
+++ b/python/pfs/drp/stella/datamodel/pfsFiberArraySet.py
@@ -62,9 +62,10 @@ def plot(self, fiberId=None, usePixels=False, ignorePixelMask=0x0, show=True):
 
         colors = matplotlib.cm.rainbow(np.linspace(0, 1, len(fiberId)))
         for ff, cc in zip(fiberId, colors):
-            index = np.where(self.fiberId == ff)[0]
-            good = (self.mask[index] & ignorePixelMask) == 0
-            axes.plot(wavelength[index][good], self.flux[index][good], ls="solid", color=cc)
+            index = np.where(self.fiberId == ff)[0][0]
+            good = ((self.mask[index] & ignorePixelMask) == 0)
+            lam = wavelength if usePixels else wavelength[index]
+            axes.plot(lam[good], self.flux[index][good], ls="solid", color=cc, label=str(ff))
 
         axes.set_xlabel(xLabel)
         axes.set_ylabel("Flux")