diff --git a/betterproto/plugin.py b/betterproto/plugin.py
index c843a6a..c867930 100755
--- a/betterproto/plugin.py
+++ b/betterproto/plugin.py
@@ -103,9 +103,9 @@ def py_type(
     message: DescriptorProto,
     descriptor: FieldDescriptorProto,
 ) -> str:
-    if descriptor.type in [1, 2, 6, 7, 15, 16]:
+    if descriptor.type in [1, 2]:
         return "float"
-    elif descriptor.type in [3, 4, 5, 13, 17, 18]:
+    elif descriptor.type in [3, 4, 5, 6, 7, 13, 15, 16, 17, 18]:
         return "int"
     elif descriptor.type == 8:
         return "bool"
diff --git a/betterproto/tests/inputs/fixed/fixed.json b/betterproto/tests/inputs/fixed/fixed.json
new file mode 100644
index 0000000..8858780
--- /dev/null
+++ b/betterproto/tests/inputs/fixed/fixed.json
@@ -0,0 +1,6 @@
+{
+  "foo": 4294967295,
+  "bar": -2147483648,
+  "baz": "18446744073709551615",
+  "qux": "-9223372036854775808"
+}
diff --git a/betterproto/tests/inputs/fixed/fixed.proto b/betterproto/tests/inputs/fixed/fixed.proto
new file mode 100644
index 0000000..50dad84
--- /dev/null
+++ b/betterproto/tests/inputs/fixed/fixed.proto
@@ -0,0 +1,8 @@
+syntax = "proto3";
+
+message Test {
+  fixed32 foo = 1;
+  sfixed32 bar = 2;
+  fixed64 baz = 3;
+  sfixed64 qux = 4;
+}