diff --git a/manimlib/animation/fading.py b/manimlib/animation/fading.py
index a209fb32..c4840ab8 100644
--- a/manimlib/animation/fading.py
+++ b/manimlib/animation/fading.py
@@ -164,10 +164,10 @@ class VFadeIn(Animation):
         alpha: float
     ) -> None:
         submob.set_stroke(
-            opacity=float(interpolate(0, start.get_stroke_opacity(), alpha))
+            opacity=interpolate(0, start.get_stroke_opacity(), alpha)
         )
         submob.set_fill(
-            opacity=float(interpolate(0, start.get_fill_opacity(), alpha))
+            opacity=interpolate(0, start.get_fill_opacity(), alpha)
         )
 
 
diff --git a/manimlib/mobject/mobject.py b/manimlib/mobject/mobject.py
index 687f96f8..159c8508 100644
--- a/manimlib/mobject/mobject.py
+++ b/manimlib/mobject/mobject.py
@@ -1361,7 +1361,7 @@ class Mobject(object):
                     rgbs = resize_with_interpolation(rgbs, len(data))
                 data[name][:, :3] = rgbs
             if opacity is not None:
-                if not isinstance(opacity, (float, int)):
+                if not isinstance(opacity, (float, int, np.floating)):
                     opacity = resize_with_interpolation(np.array(opacity), len(data))
                 data[name][:, 3] = opacity
         return self
diff --git a/manimlib/mobject/types/vectorized_mobject.py b/manimlib/mobject/types/vectorized_mobject.py
index 607951fd..1db4d9c8 100644
--- a/manimlib/mobject/types/vectorized_mobject.py
+++ b/manimlib/mobject/types/vectorized_mobject.py
@@ -185,7 +185,7 @@ class VMobject(Mobject):
         if width is not None:
             for mob in self.get_family(recurse):
                 data = mob.data if mob.get_num_points() > 0 else mob._data_defaults
-                if isinstance(width, (float, int)):
+                if isinstance(width, (float, int, np.floating)):
                     data['stroke_width'][:, 0] = width
                 else:
                     data['stroke_width'][:, 0] = resize_with_interpolation(