diff --git a/pytato/visualization.py b/pytato/visualization.py
index 421ad2af746a510c694f47328f2e163772d64c68..77392180a3834b6ce833cedb47b7f9d9760fbd15 100644
--- a/pytato/visualization.py
+++ b/pytato/visualization.py
@@ -92,7 +92,7 @@ class ArrayToDotNodeInfoMapper(pytato.transform.Mapper):
             return
         info = self.get_common_dot_info(expr)
 
-        for field in expr.fields:
+        for field in expr._fields:
             if field in info.fields:
                 continue
             attr = getattr(expr, field)