diff --git a/apps/comment/models.py b/apps/comment/models.py
index 7844b29c..a7645ed0 100644
--- a/apps/comment/models.py
+++ b/apps/comment/models.py
@@ -7,6 +7,7 @@ from account.models import User
 from translation.models import Language
 from utils.models import ProjectBaseMixin
 from utils.querysets import ContentTypeQuerySetMixin
+from django.core.validators import MaxValueValidator, MinValueValidator
 
 
 class CommentQuerySet(ContentTypeQuerySetMixin):
@@ -64,7 +65,9 @@ class Comment(ProjectBaseMixin):
     )
 
     text = models.TextField(verbose_name=_('Comment text'))
-    mark = models.PositiveIntegerField(blank=True, null=True, default=None, verbose_name=_('Mark'))
+    mark = models.PositiveIntegerField(validators=[
+        MinValueValidator(0), MaxValueValidator(5),
+    ], blank=True, null=True, default=None, verbose_name=_('Mark'))
     user = models.ForeignKey('account.User', related_name='comments', on_delete=models.CASCADE, verbose_name=_('User'))
     old_id = models.IntegerField(null=True, blank=True, default=None)
     is_publish = models.BooleanField(default=False, verbose_name=_('Publish status'))
diff --git a/apps/comment/serializers/common.py b/apps/comment/serializers/common.py
index 2e54f0be..6f0d049d 100644
--- a/apps/comment/serializers/common.py
+++ b/apps/comment/serializers/common.py
@@ -8,8 +8,8 @@ from establishment.models import EstablishmentType
 
 class CommentBaseSerializer(serializers.ModelSerializer):
     """Comment serializer"""
-    nickname = serializers.CharField(read_only=True,
-                                     source='user.username')
+    user_name = serializers.CharField(read_only=True,
+                                      source='user.username')
     is_mine = serializers.BooleanField(read_only=True)
     profile_pic = serializers.URLField(read_only=True,
                                        source='user.cropped_image_url')
@@ -32,14 +32,14 @@ class CommentBaseSerializer(serializers.ModelSerializer):
             'created',
             'text',
             'mark',
-            'nickname',
+            'user_name',
+            'user_email',
             'profile_pic',
             'status',
             'status_display',
             'last_ip',
             'content_type',
-            'content_name',
-            'user_email'
+            'content_name'
         ]
         extra_kwargs = {
             # 'status': {'read_only': True},
@@ -54,4 +54,3 @@ class CommentBaseSerializer(serializers.ModelSerializer):
         return establishment_serializers.EstablishmentTypeBaseSerializer(
             instance.content_object.establishment_type
         ).data
-