diff --git a/lindi/LindiH5ZarrStore/LindiH5ZarrStore.py b/lindi/LindiH5ZarrStore/LindiH5ZarrStore.py
index 82373eb..47f9168 100644
--- a/lindi/LindiH5ZarrStore/LindiH5ZarrStore.py
+++ b/lindi/LindiH5ZarrStore/LindiH5ZarrStore.py
@@ -69,7 +69,7 @@ def __init__(
     def from_file(
         hdf5_file_name_or_url: str,
         *,
-        opts: LindiH5ZarrStoreOpts = LindiH5ZarrStoreOpts(),
+        opts: Union[LindiH5ZarrStoreOpts, None] = None,
         url: Union[str, None] = None,
         local_cache: Union[LocalCache, None] = None
     ):
@@ -80,7 +80,7 @@ def from_file(
         ----------
         hdf5_file_name_or_url : str
             The name of the HDF5 file or a URL to the HDF5 file.
-        opts : LindiH5ZarrStoreOpts
+        opts : LindiH5ZarrStoreOpts or None
             Options for the store.
         url : str or None
             If hdf5_file_name_or_url is a local file name, then this can
@@ -93,6 +93,8 @@ def from_file(
             A local cache to use when reading chunks from a remote file. If None,
             then no local cache is used.
         """
+        if opts is None:
+            opts = LindiH5ZarrStoreOpts()  # default options
         if hdf5_file_name_or_url.startswith(
             "http://"
         ) or hdf5_file_name_or_url.startswith("https://"):
diff --git a/lindi/LindiH5ZarrStore/LindiH5ZarrStoreOpts.py b/lindi/LindiH5ZarrStore/LindiH5ZarrStoreOpts.py
index 07a3ea8..a99341a 100644
--- a/lindi/LindiH5ZarrStore/LindiH5ZarrStoreOpts.py
+++ b/lindi/LindiH5ZarrStore/LindiH5ZarrStoreOpts.py
@@ -2,7 +2,7 @@
 from dataclasses import dataclass
 
 
-@dataclass
+@dataclass(frozen=True)
 class LindiH5ZarrStoreOpts:
     """
     Options for the LindiH5ZarrStore class.
diff --git a/lindi/LindiH5pyFile/LindiH5pyFile.py b/lindi/LindiH5pyFile/LindiH5pyFile.py
index 16baecb..aa891a1 100644
--- a/lindi/LindiH5pyFile/LindiH5pyFile.py
+++ b/lindi/LindiH5pyFile/LindiH5pyFile.py
@@ -55,7 +55,7 @@ def from_lindi_file(url_or_path: str, *, mode: LindiFileMode = "r", staging_area
         return LindiH5pyFile.from_reference_file_system(url_or_path, mode=mode, staging_area=staging_area, local_cache=local_cache, local_file_path=local_file_path)
 
     @staticmethod
-    def from_hdf5_file(url_or_path: str, *, mode: LindiFileMode = "r", local_cache: Union[LocalCache, None] = None, zarr_store_opts: LindiH5ZarrStoreOpts = LindiH5ZarrStoreOpts()):
+    def from_hdf5_file(url_or_path: str, *, mode: LindiFileMode = "r", local_cache: Union[LocalCache, None] = None, zarr_store_opts: Union[LindiH5ZarrStoreOpts, None] = None):
         """
         Create a LindiH5pyFile from a URL or path to an HDF5 file.
 
@@ -68,6 +68,8 @@ def from_hdf5_file(url_or_path: str, *, mode: LindiFileMode = "r", local_cache:
             h5py.File for more information on the modes, by default "r".
         local_cache : Union[LocalCache, None], optional
             The local cache to use for caching data chunks, by default None.
+        zarr_store_opts : Union[LindiH5ZarrStoreOpts, None], optional
+            The options to use for the zarr store, by default None.
         """
         from ..LindiH5ZarrStore.LindiH5ZarrStore import LindiH5ZarrStore  # avoid circular import
         if mode != "r":