diff --git a/API.md b/API.md
index 1d48ea2..33139d5 100644
--- a/API.md
+++ b/API.md
@@ -618,10 +618,9 @@ data.
 
 - **Description**
 
-    Removes source tag and merges all of its usages to the target tag. Source
-    tag properties such as category, tag relations etc. do not get transferred
-    and are discarded. The target tag effectively remains unchanged with the
-    exception of the set of posts it's used in.
+    Removes source tag and merges all of its usages, suggestions and
+    implications to the target tag. Other tag properties such as category and
+    aliases do not get transferred and are discarded.
 
 ## Listing tag siblings
 - **Request**
diff --git a/client/html/tag_merge.tpl b/client/html/tag_merge.tpl
index 5c724c9..ea1a7ec 100644
--- a/client/html/tag_merge.tpl
+++ b/client/html/tag_merge.tpl
@@ -1,14 +1,14 @@
 <div class='tag-merge'>
     <form>
-        <p>Proceeding will remove this tag and retag its posts with the tag
-        specified below. Aliases, suggestions and implications are discarded
-        and need to be handled manually.</p>
-
         <ul>
             <li class='target'>
                 <%= ctx.makeTextInput({required: true, text: 'Target tag', pattern: ctx.tagNamePattern}) %>
             </li>
-            <li class='confirm'>
+
+            <li>
+                <p>Usages in posts, suggestions and implications will be
+                merged. Category and aliases need to be handled manually.</p>
+
                 <%= ctx.makeCheckbox({required: true, text: 'I confirm that I want to merge this tag.'}) %>
             </li>
         </ul>
diff --git a/server/szurubooru/func/posts.py b/server/szurubooru/func/posts.py
index 1ca70fc..e03fe63 100644
--- a/server/szurubooru/func/posts.py
+++ b/server/szurubooru/func/posts.py
@@ -449,18 +449,18 @@ def merge_posts(source_post, target_post, replace_content):
         raise InvalidPostRelationError('Cannot merge post with itself.')
 
     def merge_tables(table, anti_dup_func, source_post_id, target_post_id):
-        table1 = table
-        table2 = sqlalchemy.orm.util.aliased(table)
-        update_stmt = (sqlalchemy.sql.expression.update(table1)
-            .where(table1.post_id == source_post_id))
+        alias1 = table
+        alias2 = sqlalchemy.orm.util.aliased(table)
+        update_stmt = (sqlalchemy.sql.expression.update(alias1)
+            .where(alias1.post_id == source_post_id))
 
         if anti_dup_func is not None:
             update_stmt = (update_stmt
                 .where(~sqlalchemy.exists()
-                    .where(anti_dup_func(table1, table2))
-                    .where(table2.post_id == target_post_id)))
+                    .where(anti_dup_func(alias1, alias2))
+                    .where(alias2.post_id == target_post_id)))
 
-        update_stmt = (update_stmt.values(post_id=target_post_id))
+        update_stmt = update_stmt.values(post_id=target_post_id)
         db.session.execute(update_stmt)
 
     def merge_tags(source_post_id, target_post_id):
@@ -488,23 +488,23 @@ def merge_posts(source_post, target_post, replace_content):
         merge_tables(db.Comment, None, source_post_id, target_post_id)
 
     def merge_relations(source_post_id, target_post_id):
-        table1 = db.PostRelation
-        table2 = sqlalchemy.orm.util.aliased(db.PostRelation)
-        update_stmt = (sqlalchemy.sql.expression.update(table1)
-            .where(table1.parent_id == source_post_id)
-            .where(table1.child_id != target_post_id)
+        alias1 = db.PostRelation
+        alias2 = sqlalchemy.orm.util.aliased(db.PostRelation)
+        update_stmt = (sqlalchemy.sql.expression.update(alias1)
+            .where(alias1.parent_id == source_post_id)
+            .where(alias1.child_id != target_post_id)
             .where(~sqlalchemy.exists()
-                .where(table2.child_id == table1.child_id)
-                .where(table2.parent_id == target_post_id))
+                .where(alias2.child_id == alias1.child_id)
+                .where(alias2.parent_id == target_post_id))
             .values(parent_id=target_post_id))
         db.session.execute(update_stmt)
 
-        update_stmt = (sqlalchemy.sql.expression.update(table1)
-            .where(table1.child_id == source_post_id)
-            .where(table1.parent_id != target_post_id)
+        update_stmt = (sqlalchemy.sql.expression.update(alias1)
+            .where(alias1.child_id == source_post_id)
+            .where(alias1.parent_id != target_post_id)
             .where(~sqlalchemy.exists()
-                .where(table2.parent_id == table1.parent_id)
-                .where(table2.child_id == target_post_id))
+                .where(alias2.parent_id == alias1.parent_id)
+                .where(alias2.child_id == target_post_id))
             .values(child_id=target_post_id))
         db.session.execute(update_stmt)
 
diff --git a/server/szurubooru/func/tags.py b/server/szurubooru/func/tags.py
index 7a4887a..fa4ee00 100644
--- a/server/szurubooru/func/tags.py
+++ b/server/szurubooru/func/tags.py
@@ -223,16 +223,49 @@ def merge_tags(source_tag, target_tag):
     assert target_tag
     if source_tag.tag_id == target_tag.tag_id:
         raise InvalidTagRelationError('Cannot merge tag with itself.')
-    pt1 = db.PostTag
-    pt2 = sqlalchemy.orm.util.aliased(db.PostTag)
 
-    update_stmt = (sqlalchemy.sql.expression.update(pt1)
-        .where(db.PostTag.tag_id == source_tag.tag_id)
-        .where(~sqlalchemy.exists()
-            .where(pt2.post_id == pt1.post_id)
-            .where(pt2.tag_id == target_tag.tag_id))
-        .values(tag_id=target_tag.tag_id))
-    db.session.execute(update_stmt)
+    def merge_posts(source_tag_id, target_tag_id):
+        alias1 = db.PostTag
+        alias2 = sqlalchemy.orm.util.aliased(db.PostTag)
+        update_stmt = (sqlalchemy.sql.expression.update(alias1)
+            .where(alias1.tag_id == source_tag_id))
+        update_stmt = (update_stmt
+            .where(~sqlalchemy.exists()
+                .where(alias1.post_id == alias2.post_id)
+                .where(alias2.tag_id == target_tag_id)))
+        update_stmt = update_stmt.values(tag_id=target_tag_id)
+        db.session.execute(update_stmt)
+
+    def merge_relations(table, source_tag_id, target_tag_id):
+        alias1 = table
+        alias2 = sqlalchemy.orm.util.aliased(table)
+        update_stmt = (sqlalchemy.sql.expression.update(alias1)
+            .where(alias1.parent_id == source_tag_id)
+            .where(alias1.child_id != target_tag_id)
+            .where(~sqlalchemy.exists()
+                .where(alias2.child_id == alias1.child_id)
+                .where(alias2.parent_id == target_tag_id))
+            .values(parent_id=target_tag_id))
+        db.session.execute(update_stmt)
+
+        update_stmt = (sqlalchemy.sql.expression.update(alias1)
+            .where(alias1.child_id == source_tag_id)
+            .where(alias1.parent_id != target_tag_id)
+            .where(~sqlalchemy.exists()
+                .where(alias2.parent_id == alias1.parent_id)
+                .where(alias2.child_id == target_tag_id))
+            .values(child_id=target_tag_id))
+        db.session.execute(update_stmt)
+
+    def merge_suggestions(source_tag_id, target_tag_id):
+        merge_relations(db.TagSuggestion, source_tag_id, target_tag_id)
+
+    def merge_implications(source_tag_id, target_tag_id):
+        merge_relations(db.TagImplication, source_tag_id, target_tag_id)
+
+    merge_posts(source_tag.tag_id, target_tag.tag_id)
+    merge_suggestions(source_tag.tag_id, target_tag.tag_id)
+    merge_implications(source_tag.tag_id, target_tag.tag_id)
     delete(source_tag)
 
 
diff --git a/server/szurubooru/tests/func/test_tags.py b/server/szurubooru/tests/func/test_tags.py
index f438a9d..d467499 100644
--- a/server/szurubooru/tests/func/test_tags.py
+++ b/server/szurubooru/tests/func/test_tags.py
@@ -310,7 +310,7 @@ def test_delete(tag_factory):
     assert db.session.query(db.Tag).count() == 2
 
 
-def test_merge_tags_without_usages(tag_factory):
+def test_merge_tags_deletes_source_tag(tag_factory):
     source_tag = tag_factory(names=['source'])
     target_tag = tag_factory(names=['target'])
     db.session.add_all([source_tag, target_tag])
@@ -322,7 +322,15 @@ def test_merge_tags_without_usages(tag_factory):
     assert tag is not None
 
 
-def test_merge_tags_with_usages(tag_factory, post_factory):
+def test_merge_tags_with_itself(tag_factory):
+    source_tag = tag_factory(names=['source'])
+    db.session.add(source_tag)
+    db.session.flush()
+    with pytest.raises(tags.InvalidTagRelationError):
+        tags.merge_tags(source_tag, source_tag)
+
+
+def test_merge_tags_moves_usages(tag_factory, post_factory):
     source_tag = tag_factory(names=['source'])
     target_tag = tag_factory(names=['target'])
     post = post_factory()
@@ -337,62 +345,7 @@ def test_merge_tags_with_usages(tag_factory, post_factory):
     assert tags.get_tag_by_name('target').post_count == 1
 
 
-def test_merge_tags_with_itself(tag_factory):
-    source_tag = tag_factory(names=['source'])
-    db.session.add(source_tag)
-    db.session.flush()
-    with pytest.raises(tags.InvalidTagRelationError):
-        tags.merge_tags(source_tag, source_tag)
-
-
-def test_merge_tags_with_its_child_relation(tag_factory, post_factory):
-    source_tag = tag_factory(names=['source'])
-    target_tag = tag_factory(names=['target'])
-    source_tag.suggestions = [target_tag]
-    source_tag.implications = [target_tag]
-    post = post_factory()
-    post.tags = [source_tag, target_tag]
-    db.session.add_all([source_tag, post])
-    db.session.flush()
-    tags.merge_tags(source_tag, target_tag)
-    db.session.flush()
-    assert tags.try_get_tag_by_name('source') is None
-    assert tags.get_tag_by_name('target').post_count == 1
-
-
-def test_merge_tags_with_its_parent_relation(tag_factory, post_factory):
-    source_tag = tag_factory(names=['source'])
-    target_tag = tag_factory(names=['target'])
-    target_tag.suggestions = [source_tag]
-    target_tag.implications = [source_tag]
-    post = post_factory()
-    post.tags = [source_tag, target_tag]
-    db.session.add_all([source_tag, target_tag, post])
-    db.session.flush()
-    tags.merge_tags(source_tag, target_tag)
-    db.session.flush()
-    assert tags.try_get_tag_by_name('source') is None
-    assert tags.get_tag_by_name('target').post_count == 1
-
-
-def test_merge_tags_clears_relations(tag_factory):
-    source_tag = tag_factory(names=['source'])
-    target_tag = tag_factory(names=['target'])
-    referring_tag = tag_factory(names=['parent'])
-    referring_tag.suggestions = [source_tag]
-    referring_tag.implications = [source_tag]
-    db.session.add_all([source_tag, target_tag, referring_tag])
-    db.session.flush()
-    assert tags.try_get_tag_by_name('parent').implications != []
-    assert tags.try_get_tag_by_name('parent').suggestions != []
-    tags.merge_tags(source_tag, target_tag)
-    db.session.commit()
-    assert tags.try_get_tag_by_name('source') is None
-    assert tags.try_get_tag_by_name('parent').implications == []
-    assert tags.try_get_tag_by_name('parent').suggestions == []
-
-
-def test_merge_tags_when_target_exists(tag_factory, post_factory):
+def test_merge_tags_doesnt_duplicate_usages(tag_factory, post_factory):
     source_tag = tag_factory(names=['source'])
     target_tag = tag_factory(names=['target'])
     post = post_factory()
@@ -407,6 +360,103 @@ def test_merge_tags_when_target_exists(tag_factory, post_factory):
     assert tags.get_tag_by_name('target').post_count == 1
 
 
+def test_merge_tags_moves_child_relations(tag_factory):
+    source_tag = tag_factory(names=['source'])
+    target_tag = tag_factory(names=['target'])
+    related_tag = tag_factory()
+    source_tag.suggestions = [related_tag]
+    source_tag.implications = [related_tag]
+    db.session.add_all([source_tag, target_tag, related_tag])
+    db.session.commit()
+    assert source_tag.suggestion_count == 1
+    assert source_tag.implication_count == 1
+    assert target_tag.suggestion_count == 0
+    assert target_tag.implication_count == 0
+    tags.merge_tags(source_tag, target_tag)
+    db.session.commit()
+    assert tags.try_get_tag_by_name('source') is None
+    assert tags.get_tag_by_name('target').suggestion_count == 1
+    assert tags.get_tag_by_name('target').implication_count == 1
+
+
+def test_merge_tags_doesnt_duplicate_child_relations(tag_factory):
+    source_tag = tag_factory(names=['source'])
+    target_tag = tag_factory(names=['target'])
+    related_tag = tag_factory()
+    source_tag.suggestions = [related_tag]
+    source_tag.implications = [related_tag]
+    target_tag.suggestions = [related_tag]
+    target_tag.implications = [related_tag]
+    db.session.add_all([source_tag, target_tag, related_tag])
+    db.session.commit()
+    assert source_tag.suggestion_count == 1
+    assert source_tag.implication_count == 1
+    assert target_tag.suggestion_count == 1
+    assert target_tag.implication_count == 1
+    tags.merge_tags(source_tag, target_tag)
+    db.session.commit()
+    assert tags.try_get_tag_by_name('source') is None
+    assert tags.get_tag_by_name('target').suggestion_count == 1
+    assert tags.get_tag_by_name('target').implication_count == 1
+
+
+def test_merge_tags_moves_parent_relations(tag_factory):
+    source_tag = tag_factory(names=['source'])
+    target_tag = tag_factory(names=['target'])
+    related_tag = tag_factory(names=['related'])
+    related_tag.suggestions = [related_tag]
+    related_tag.implications = [related_tag]
+    db.session.add_all([source_tag, target_tag, related_tag])
+    db.session.commit()
+    assert source_tag.suggestion_count == 0
+    assert source_tag.implication_count == 0
+    assert target_tag.suggestion_count == 0
+    assert target_tag.implication_count == 0
+    tags.merge_tags(source_tag, target_tag)
+    db.session.commit()
+    assert tags.try_get_tag_by_name('source') is None
+    assert tags.get_tag_by_name('related').suggestion_count == 1
+    assert tags.get_tag_by_name('related').suggestion_count == 1
+    assert tags.get_tag_by_name('target').suggestion_count == 0
+    assert tags.get_tag_by_name('target').implication_count == 0
+
+
+def test_merge_tags_doesnt_create_relation_loop_for_children(tag_factory):
+    source_tag = tag_factory(names=['source'])
+    target_tag = tag_factory(names=['target'])
+    source_tag.suggestions = [target_tag]
+    source_tag.implications = [target_tag]
+    db.session.add_all([source_tag, target_tag])
+    db.session.commit()
+    assert source_tag.suggestion_count == 1
+    assert source_tag.implication_count == 1
+    assert target_tag.suggestion_count == 0
+    assert target_tag.implication_count == 0
+    tags.merge_tags(source_tag, target_tag)
+    db.session.commit()
+    assert tags.try_get_tag_by_name('source') is None
+    assert tags.get_tag_by_name('target').suggestion_count == 0
+    assert tags.get_tag_by_name('target').implication_count == 0
+
+
+def test_merge_tags_doesnt_create_relation_loop_for_parents(tag_factory):
+    source_tag = tag_factory(names=['source'])
+    target_tag = tag_factory(names=['target'])
+    target_tag.suggestions = [source_tag]
+    target_tag.implications = [source_tag]
+    db.session.add_all([source_tag, target_tag])
+    db.session.commit()
+    assert source_tag.suggestion_count == 0
+    assert source_tag.implication_count == 0
+    assert target_tag.suggestion_count == 1
+    assert target_tag.implication_count == 1
+    tags.merge_tags(source_tag, target_tag)
+    db.session.commit()
+    assert tags.try_get_tag_by_name('source') is None
+    assert tags.get_tag_by_name('target').suggestion_count == 0
+    assert tags.get_tag_by_name('target').implication_count == 0
+
+
 def test_create_tag(fake_datetime):
     with patch('szurubooru.func.tags.update_tag_names'), \
             patch('szurubooru.func.tags.update_tag_category_name'), \