diff --git a/releasenotes/notes/victoria-flavor-optional.yaml b/releasenotes/notes/victoria-flavor-optional.yaml
new file mode 100644
index 00000000..b538014a
--- /dev/null
+++ b/releasenotes/notes/victoria-flavor-optional.yaml
@@ -0,0 +1,4 @@
+---
+features:
+  - Change flavor as an optional parameter (``--flavor``) for creating
+    instance. When creating replicas, flavor is not requried.
diff --git a/troveclient/osc/v1/database_instances.py b/troveclient/osc/v1/database_instances.py
index ffda02b5..2d186265 100644
--- a/troveclient/osc/v1/database_instances.py
+++ b/troveclient/osc/v1/database_instances.py
@@ -227,7 +227,7 @@ class CreateDatabaseInstance(command.ShowOne):
             help=_("Name of the instance."),
         )
         parser.add_argument(
-            'flavor',
+            '--flavor',
             metavar='<flavor>',
             type=str,
             help=_("A flavor ID."),
@@ -241,7 +241,7 @@ class CreateDatabaseInstance(command.ShowOne):
                    "Required when volume support is enabled."),
         )
         parser.add_argument(
-            '--volume_type',
+            '--volume-type',
             metavar='<volume_type>',
             type=str,
             default=None,
@@ -268,7 +268,7 @@ class CreateDatabaseInstance(command.ShowOne):
             help=_("A backup name or ID."),
         )
         parser.add_argument(
-            '--availability_zone',
+            '--availability-zone',
             metavar='<availability_zone>',
             default=None,
             help=_("The Zone hint to give to Nova."),
@@ -280,7 +280,7 @@ class CreateDatabaseInstance(command.ShowOne):
             help=_("A datastore name or ID."),
         )
         parser.add_argument(
-            '--datastore_version',
+            '--datastore-version',
             metavar='<datastore_version>',
             default=None,
             help=_("A datastore version name or ID."),
@@ -298,13 +298,13 @@ class CreateDatabaseInstance(command.ShowOne):
             help=_("ID of the configuration group to attach to the instance."),
         )
         parser.add_argument(
-            '--replica_of',
+            '--replica-of',
             metavar='<source_instance>',
             default=None,
             help=_("ID or name of an existing instance to replicate from."),
         )
         parser.add_argument(
-            '--replica_count',
+            '--replica-count',
             metavar='<count>',
             type=int,
             default=None,
@@ -353,7 +353,6 @@ class CreateDatabaseInstance(command.ShowOne):
     def take_action(self, parsed_args):
         database = self.app.client_manager.database
         db_instances = database.instances
-        flavor_id = parsed_args.flavor
 
         volume = None
         if parsed_args.size is not None and parsed_args.size <= 0:
@@ -409,7 +408,7 @@ class CreateDatabaseInstance(command.ShowOne):
 
         instance = db_instances.create(
             parsed_args.name,
-            flavor_id,
+            flavor_id=parsed_args.flavor,
             volume=volume,
             databases=databases,
             users=users,
diff --git a/troveclient/tests/osc/v1/test_database_instances.py b/troveclient/tests/osc/v1/test_database_instances.py
index bb3950df..630ba1d5 100644
--- a/troveclient/tests/osc/v1/test_database_instances.py
+++ b/troveclient/tests/osc/v1/test_database_instances.py
@@ -204,15 +204,15 @@ class TestDatabaseInstanceCreate(TestInstances):
     @mock.patch.object(utils, 'find_resource')
     def test_instance_create(self, mock_find):
         mock_find.id.side_effect = ['test', 'mod_id']
-        args = ['test-name', '103',
+        args = ['test-name', '--flavor', '103',
                 '--size', '1',
                 '--databases', 'db1', 'db2',
                 '--users', 'u1:111', 'u2:111',
                 '--datastore', "datastore",
-                '--datastore_version', "datastore_version",
+                '--datastore-version', "datastore_version",
                 '--nic', 'net-id=net1',
-                '--replica_of', 'test',
-                '--replica_count', '4',
+                '--replica-of', 'test',
+                '--replica-count', '4',
                 '--module', 'mod_id',
                 '--is-public',
                 '--allowed-cidr', '10.0.0.1/24',
diff --git a/troveclient/v1/instances.py b/troveclient/v1/instances.py
index 15725a30..2ff17f3b 100644
--- a/troveclient/v1/instances.py
+++ b/troveclient/v1/instances.py
@@ -89,18 +89,20 @@ class Instances(base.ManagerWithFind):
             auth_url, user, key, auth_version=auth_version,
             os_options=os_options)
 
-    def create(self, name, flavor_id, volume=None, databases=None, users=None,
-               restorePoint=None, availability_zone=None, datastore=None,
-               datastore_version=None, nics=None, configuration=None,
-               replica_of=None, replica_count=None, modules=None,
-               locality=None, region_name=None, access=None, **kwargs):
+    def create(self, name, flavor_id=None, volume=None, databases=None,
+               users=None, restorePoint=None, availability_zone=None,
+               datastore=None, datastore_version=None, nics=None,
+               configuration=None, replica_of=None, replica_count=None,
+               modules=None, locality=None, region_name=None, access=None,
+               **kwargs):
         """Create (boot) a new instance."""
 
         body = {"instance": {
             "name": name,
-            "flavorRef": flavor_id
         }}
         datastore_obj = {}
+        if flavor_id:
+            body["instance"]["flavorRef"] = flavor_id
         if volume:
             body["instance"]["volume"] = volume
         if databases: