diff --git a/lib/galaxy/datatypes/binary.py b/lib/galaxy/datatypes/binary.py
index 4bcb3f8488a5..4454344d6d48 100644
--- a/lib/galaxy/datatypes/binary.py
+++ b/lib/galaxy/datatypes/binary.py
@@ -1505,7 +1505,7 @@ def _layercountsize(tmp, lennames=0):
                     count = len(tmp.dtype)
                     size = int(tmp.size)
                 else:
-                    layers = list(tmp.attrs)
+                    layers = list(tmp.keys())
                     count = len(layers)
                     size = lennames
                 return (layers, count, size)