diff --git a/yt/frontends/ytdata/data_structures.py b/yt/frontends/ytdata/data_structures.py
index 810c9905f88..97e4b38eddd 100644
--- a/yt/frontends/ytdata/data_structures.py
+++ b/yt/frontends/ytdata/data_structures.py
@@ -425,6 +425,8 @@ def Children(self):
 
 
 class YTDataHierarchy(GridIndex):
+    min_level = 0
+
     def __init__(self, ds, dataset_type=None):
         self.dataset_type = dataset_type
         self.float_type = "float64"