diff --git a/lib/statsd/instrument/metric.rb b/lib/statsd/instrument/metric.rb
index 20226213..82e8ae2a 100644
--- a/lib/statsd/instrument/metric.rb
+++ b/lib/statsd/instrument/metric.rb
@@ -101,8 +101,8 @@ def inspect
   # @param tags [Array<String>, Hash<String, String>, nil] Tags specified in any form.
   # @return [Array<String>, nil] the list of tags in canonical form.
   def self.normalize_tags(tags)
-    return if tags.nil?
-    tags = tags.map { |k, v| "#{k.to_s.tr(':', '')}:#{v.to_s.tr(':', '')}" } if tags.is_a?(Hash)
+    return unless tags
+    tags = tags.map { |k, v| k.to_s + ":".freeze + v.to_s } if tags.is_a?(Hash)
     tags.map { |tag| tag.tr('|,'.freeze, ''.freeze) }
   end
 end
diff --git a/test/metric_test.rb b/test/metric_test.rb
index 8f591e3d..ac9ec19a 100644
--- a/test/metric_test.rb
+++ b/test/metric_test.rb
@@ -26,7 +26,7 @@ def test_name_prefix
 
   def test_handle_bad_tags
     assert_equal ['ignored'], StatsD::Instrument::Metric.normalize_tags(['igno|red'])
-    assert_equal ['lolclass:omglol'], StatsD::Instrument::Metric.normalize_tags({ :"lol::class" => "omg::lol" })
+    assert_equal ['lol::class:omg::lol'], StatsD::Instrument::Metric.normalize_tags({ :"lol::class" => "omg::lol" })
   end
 
   def test_rewrite_tags_provided_as_hash