diff --git a/extended_query_builder.go b/extended_query_builder.go
index e87b5edd..8b250685 100644
--- a/extended_query_builder.go
+++ b/extended_query_builder.go
@@ -83,18 +83,16 @@ func (eqb *extendedQueryBuilder) encodeExtendedParamValue(ci *pgtype.ConnInfo, o
 		return eqb.encodeExtendedParamValue(ci, oid, formatCode, arg)
 	}
 
-	if dt, ok := ci.DataTypeForOID(oid); ok {
-		if dt.Codec != nil {
-			buf, err := ci.Encode(oid, formatCode, arg, eqb.paramValueBytes)
-			if err != nil {
-				return nil, err
-			}
-			if buf == nil {
-				return nil, nil
-			}
-			eqb.paramValueBytes = buf
-			return eqb.paramValueBytes[pos:], nil
+	if _, ok := ci.DataTypeForOID(oid); ok {
+		buf, err := ci.Encode(oid, formatCode, arg, eqb.paramValueBytes)
+		if err != nil {
+			return nil, err
 		}
+		if buf == nil {
+			return nil, nil
+		}
+		eqb.paramValueBytes = buf
+		return eqb.paramValueBytes[pos:], nil
 	}
 
 	if strippedArg, ok := stripNamedType(&refVal); ok {
diff --git a/pgtype/pgtype.go b/pgtype/pgtype.go
index 9a39e3ff..5bb04d71 100644
--- a/pgtype/pgtype.go
+++ b/pgtype/pgtype.go
@@ -331,15 +331,7 @@ func NewConnInfo() *ConnInfo {
 func (ci *ConnInfo) RegisterDataType(t DataType) {
 	ci.oidToDataType[t.OID] = &t
 	ci.nameToDataType[t.Name] = &t
-
-	{
-		var formatCode int16
-		if t.Codec != nil {
-			formatCode = t.Codec.PreferredFormat()
-		}
-		ci.oidToFormatCode[t.OID] = formatCode
-	}
-
+	ci.oidToFormatCode[t.OID] = t.Codec.PreferredFormat()
 	ci.reflectTypeToDataType = nil // Invalidated by type registration
 }
 
@@ -992,7 +984,7 @@ func (ci *ConnInfo) PlanScan(oid uint32, formatCode int16, dst interface{}) Scan
 		}
 	}
 
-	if dt != nil && dt.Codec != nil {
+	if dt != nil {
 		if plan := dt.Codec.PlanScan(ci, oid, formatCode, dst, false); plan != nil {
 			return plan
 		}
@@ -1105,7 +1097,7 @@ func (ci *ConnInfo) PlanEncode(oid uint32, format int16, value interface{}) Enco
 		}
 	}
 
-	if dt != nil && dt.Codec != nil {
+	if dt != nil {
 		if plan := dt.Codec.PlanEncode(ci, oid, format, value); plan != nil {
 			return plan
 		}
diff --git a/rows.go b/rows.go
index e076ce43..5a4bc9a9 100644
--- a/rows.go
+++ b/rows.go
@@ -246,13 +246,11 @@ func (rows *connRows) Values() ([]interface{}, error) {
 		}
 
 		if dt, ok := rows.connInfo.DataTypeForOID(fd.DataTypeOID); ok {
-			if dt.Codec != nil {
-				value, err := dt.Codec.DecodeValue(rows.connInfo, fd.DataTypeOID, fd.Format, buf)
-				if err != nil {
-					rows.fatal(err)
-				}
-				values = append(values, value)
+			value, err := dt.Codec.DecodeValue(rows.connInfo, fd.DataTypeOID, fd.Format, buf)
+			if err != nil {
+				rows.fatal(err)
 			}
+			values = append(values, value)
 		} else {
 			switch fd.Format {
 			case TextFormatCode:
diff --git a/values.go b/values.go
index 3cb27bbf..a6fdcc86 100644
--- a/values.go
+++ b/values.go
@@ -79,17 +79,15 @@ func convertSimpleArgument(ci *pgtype.ConnInfo, arg interface{}) (interface{}, e
 		return int64(arg), nil
 	}
 
-	if dt, found := ci.DataTypeForValue(arg); found {
-		if dt.Codec != nil {
-			buf, err := ci.Encode(0, TextFormatCode, arg, nil)
-			if err != nil {
-				return nil, err
-			}
-			if buf == nil {
-				return nil, nil
-			}
-			return string(buf), nil
+	if _, found := ci.DataTypeForValue(arg); found {
+		buf, err := ci.Encode(0, TextFormatCode, arg, nil)
+		if err != nil {
+			return nil, err
 		}
+		if buf == nil {
+			return nil, nil
+		}
+		return string(buf), nil
 	}
 
 	if refVal.Kind() == reflect.Ptr {
@@ -125,20 +123,18 @@ func encodePreparedStatementArgument(ci *pgtype.ConnInfo, buf []byte, oid uint32
 		return encodePreparedStatementArgument(ci, buf, oid, arg)
 	}
 
-	if dt, ok := ci.DataTypeForOID(oid); ok {
-		if dt.Codec != nil {
-			sp := len(buf)
-			buf = pgio.AppendInt32(buf, -1)
-			argBuf, err := ci.Encode(oid, BinaryFormatCode, arg, buf)
-			if err != nil {
-				return nil, err
-			}
-			if argBuf != nil {
-				buf = argBuf
-				pgio.SetInt32(buf[sp:], int32(len(buf[sp:])-4))
-			}
-			return buf, nil
+	if _, ok := ci.DataTypeForOID(oid); ok {
+		sp := len(buf)
+		buf = pgio.AppendInt32(buf, -1)
+		argBuf, err := ci.Encode(oid, BinaryFormatCode, arg, buf)
+		if err != nil {
+			return nil, err
 		}
+		if argBuf != nil {
+			buf = argBuf
+			pgio.SetInt32(buf[sp:], int32(len(buf[sp:])-4))
+		}
+		return buf, nil
 	}
 
 	if strippedArg, ok := stripNamedType(&refVal); ok {