diff --git a/src/napari_stress/_reconstruction/fit_utils.py b/src/napari_stress/_reconstruction/fit_utils.py
index 2e03dae5..7c37e73c 100644
--- a/src/napari_stress/_reconstruction/fit_utils.py
+++ b/src/napari_stress/_reconstruction/fit_utils.py
@@ -183,7 +183,7 @@ def _fancy_edge_fit(
         DESCRIPTION.
     """
     params = _function_args_to_list(selected_edge_func)[1:]
-    array = [x for x in array if not np.isnan(x)]  # filter out nans
+    array = array[~np.isnan(array)]  # filter out nans
     try:
         if selected_edge_func == _sigmoid:
             # estimate parameters and trim intensity array
@@ -252,8 +252,7 @@ def estimate_fit_parameters(intensity):
     """
     # Check if there are too few points
     if len(intensity) < 5:
-        print("Warning: Too few points in trace (length < 5)")
-        return [np.nan] * 5, intensity, intensity
+        raise ValueError("Warning: Too few points in trace (length < 5)")
 
     # Calculate the first derivative (dY)
     dY = 0.5 * (